Nothing lasts forever, and that is especially true in the National Football League.
As on-field organized activities begin around the league, many veterans find themselves in danger of losing their starting jobs or being knocked off the roster entirely.
Most of the latter won't happen until the cuts to 53 players, but the process advances to warp speed with OTAs and minicamps where veteran newcomers and rookies arrive to increase the competition. Of course, the process began once the season ended with teams releasing players and the expiration of contracts on March 14.
Consider that of the 397 unrestricted free agents at the beginning of the league year, 142 remain unsigned and that figure does not include players that have announced their retirement. Of those 142, 41 ended the 2017 season on reserve/injured. There are another 41 players unsigned that became free agents when their teams elected not to tender them as restricted or exclusive-rights free agents. Of those 41, 32 were on reserve/injured at the conclusion of last season.
With the help of The Sports Xchange/NFLDraftScout.com correspondents in each city, we present a team-by-team analysis of a veteran on the bubble. It's notable that 27 rookies are mentioned as a reason why the player could be in danger.
There are 19 offensive players cited, of which seven are offensive linemen and another seven are wide receivers. Of the 11 defensive players fighting for their jobs, five are defensive linemen and four are linebackers.
Those players include wide receivers Kevin White (Bears) and Breshad Perriman (Bengals), Jaguars defensive end Dante Fowler Jr., Cardinals guard Mike Iupati, Packers tackle Bryan Bulaga, Lions running back Ameer Abdullah and Vikings defensive end Brian Robison.
--T Chaz Green: Green is a former third-round pick who has yet to develop into a quality backup. It was his nightmarish performance against the Atlanta Falcons last season that has been the backdrop of the offensive line upgrades throughout the offseason, in free agency and the draft. It will be hard for him to survive.
NEW YORK GIANTS
--K Aldrick Rosas: Rosas, who is entering his second season, has a strong leg but last year struggled with field-goal kicking. He converted 72 percent of his attempts, putting the Giants 31st in the league in field-goal conversions. His struggles with accuracy are a big reason why he's going to have competition for his job. The Giants currently have the unproven Marshall Koehn on the roster, but don't be surprised if both young kickers struggle and in what's left of the spring, a veteran is added as additional competition.
--RB Wendell Smallwood: The 2016 fifth-round pick out of West Virginia had just 47 carries last season and was inactive for six of the Eagles' last seven regular-season games and all three of their playoff games. The Eagles' decision to bring back 35-year-old Darren Sproles, and the emergence of Corey Clement last year could make Smallwood odd man out. Particularly if 2017 fourth-round pick Donnel Pumphrey or undrafted free agent Josh Adams have strong springs and summers.
--DE Ziggy Hood: A veteran presence on a young defensive line for two years now, but as the Redskins continue to invest in the line with first-round draft pick Da'Ron Payne and fifth-round draft pick Tim Settle joining Jonathan Allen, the 2017 first-round pick, it's possible Hood loses out. Matt Ioannidis and Anthony Lanier are two more young linemen who showed promise last season.
--WR Kevin White: The Bears declined the option for White's fifth season, so it has become a make-or-break year for the seventh overall pick of the 2015 draft. To say he has done little to date probably inflates the word "little." He has been in five games, has 21 catches for only 193 yards, no touchdowns and has been on the field for 238 plays in three seasons. A free agent now after this season, they have given him this one last chance to prove himself. It's last year's Kyle Fuller situation all over again, but Fuller at least had one decent season as a rookie to support hope he'd develop. With 12 other wide receivers on the roster heading into the offseason workouts, it's not beyond the realm of possibility they could simply decide the $5.3 million dead cap hit would be easily digested because of a good overall cap situation. Still, he will get every opportunity at OTAs, minicamp, training camp and preseason to show he's legit.
--RB Ameer Abdullah: The worst rushing team in the NFL suddenly has a logjam at the running back position. Second-round pick Kerryon Johnson and free-agent addition LeGarrette Blount sit atop the depth chart, and Theo Riddick is one of the best pass-catching backs in the NFL. Abdullah, meanwhile, is in state of limbo as a solid insurance option but someone with no clear-cut role in 2018. A second-round pick in 2015, Abdullah hasn't lived up to his billing yet for a variety of reasons, including some out of his control. But he lost his job last season and the Lions drafted over him this year, which tells you all you need to know about his future in Detroit.
GREEN BAY PACKERS
--RT Bryan Bulaga: The veteran is trying to come back from his second torn ACL. The Packers asked Bulaga to take a pay cut earlier this offseason and he refused. Perhaps the only think saving Bulaga for now is Green Bay is extremely thin on the right side of the offensive line. If someone from that unproven lot emerges, though, Bulaga's days as a Packer could be over.
--DE Brian Robison: The 35-year-old lost his starting job at left end to Danielle Hunter last year. This year, he could lose his spot on a roster that has added depth and versatility to the defensive line. Jalyn Holmes, a fourth-round draft pick out of Ohio State, was selected because eventually he will give the Vikings everything Robison can do. It's just a matter of whether that will be this year or next year. Robison can back up left end and play a significant role as an interior rusher in head coach Mike Zimmer's third-down packages. He has considerable experience, which is especially useful when Zimmer puts him in a situation where he needs to read the offense while roaming the line of scrimmage before the snap. Holmes played end in college, but the Vikings see him as an under tackle that will bring unusual interior rush skills. If the 6-foot-5, 270-pounder develops faster than expected, Robison could become expendable. He's due to make $3.2 million and his only guarantee is $1.25 million for injury only.
--CB (nickel) Brian Poole: It's getting crowded in the Falcons secondary at cornerback with second-round pick Isaiah Oliver on board. Poole was already going to have to beat out Damontae Kazee. If Oliver comes along quickly, then Robert Alford may be moved inside to compete for the nickel spot. Poole is tough, but the Falcons are clearly trying to upgrade the speed at the position.
--CB Captain Munnerlyn: The Panthers have been trending younger at cornerback and they've added Ross Cockrell to shore up some of the needed experience at the position. Munnerlyn's return to the Panthers last year didn't result in the same type of production that he had during his first go-around in Carolina before he played for the Minnesota Vikings. He also didn't react all that well to a reduced role last season and so his attitude might be worth monitoring as the depth chart takes shape.
NEW ORLEANS SAINTS
--WR Brandon Coleman: The Saints let Coleman test the market after not tendering him as a restricted free agent as a restricted free agent, meaning they were prepared to move on without him. Eventually they brought him back, but they also brought in former Bears WR Cameron Meredith and third-round draft choice Tre'Quan Smith from Central Florida to provide depth behind Michael Thomas and Ted Ginn Jr. In addition, Tommylee Lewis has value as a return specialist, leaving Coleman with a lot of competition to make the roster.
TAMPA BAY BUCCANEERS
--G J.R. Sweezy: After signing as a free agent from Seattle in 2016, he missed the year recovering from back surgery. Sweezy started in 2017, but he is likely to miss OTAs recovering from knee surgery. The Bucs plan to play second-year pro Caleb Benenoch at right guard and also used a third-round pick on Alex Cappa from Division II Humboldt State.
--LG Mike Iupati: When healthy, Iupati is one of the best left guards in the business. The problem is, he's had problems staying on the field and that always makes an NFL team worrisome. It also puts a target on a veteran such as Iupati. Especially his pricy salary. If for any reason, Iupati starts having more issues with his feet or his ankle or his knees, keep an eye on rookie Mason Cole, who started 51 consecutive games at Michigan. The Cardinals see Cole as a center and a guard and aren't afraid to use him at either spot. Head coach Steve Wilks and general manager Steve Keim have both said Cole is capable of stepping in and playing right away if there were a need along the team's retooled offensive line. If Iupati is hobbling for whatever reason, Cole will get his shot.
LOS ANGELES RAMS
--T Darrell Williams: The Rams drafted Joseph Noteboom and Jamil Demby in April, and the investment signals a short-range and long-range plan to beef up their tackle depth while grooming an eventual replacement for veteran left tackle Andrew Whitworth. Williams played well last year in limited playing time, but he will get pushed by some newcomers looking to earn a backup role on a talented line.
SAN FRANCISCO 49ERS
--TE Garrett Celek: The 49ers have been the team to call late in training camp if you need a dependable tight end in recent years, and this summer could be no different. With George Kittle pretty much locked into the starting job, the 49ers have at least three serious candidates to duel Celek for complementary roles. Cole Hikutini, a 2017 draft pick who came in highly regarded, would seem fully capable of being Kittle's chief sidekick, while reserve/future contract holdover Cole Wick and undrafted free agent Ross Dwelley have the potential to surprise in camp.
P Jon Ryan: With the selection of Texas punter Michael Dickson in the fifth round, Ryan's 10-year run with the Seahawks appears to be nearing its end. The Seahawks have said they want Dickson and Ryan to compete for the job, but Dickson will get the benefit of the doubt after Seattle traded up to select him.
--LT Jordan Mills: He's been the starter for most of his three seasons in Buffalo, but the Bills would certainly prefer an upgrade. Whether one is currently on the roster is unknown, but the team did sign Marshall Newhouse as a mid-tier free agent and the eight-year veteran has 70 career NFL starts.
--TE MarQueis Gray: The Dolphins drafted a pair of tight ends - Mike Gesicki in the second round and Durham Smythe in the fourth round - and that means both of the returnees, Gray and A.J. Derby might not make it to the final cut. Both rookies will be there. We'll see about the tight ends.
NEW ENGLAND PATRIOTS
--S Jordan Richards: The former second-round pick struggled in his relatively limited playing time on defense last year, especially in Super Bowl LII. His biggest contributions to date have been in the kicking game, and as a liability on defense he will be in a fight for a roster spot heading toward his fourth season.
NEW YORK JETS
--RB Thomas Rawls: The Jets scooped up the stocky 24-year-old after two years of declining production in Seattle following a promising rookie season that saw him rush for 830 yards and four touchdowns in 13 games. Injuries have slowed him, and the Jets have plenty of depth at the position, with the newly-signed Isaiah Crowell, the still-productive Bilal Powell and young Elijah McGuire, who showed flashes last season. Unless the Jets use Rawls as a goal line back, he probably won't make the team.
--WR Breshad Perriman: The former first-round pick in 2015 has not lived up to expectations. The Ravens already declined to exercise the fifth-year 2019 option on Perriman. He is also due a $649,485 bonus on the third day of Baltimore's training camp and must have a strong showing in the OTAs to earn that money. Perriman missed the entire 2015 season with a knee injury, caught 33 passes in 2016 and had just 10 receptions last season.
--S George Iloka: Maybe not a roster spot, but a starting spot. The Bengals are looking for more picks in the back end and in the second round they drafted Wake Forest safety Jessie Bates III. That could be putting heat on Iloka, who often leaves the box to Shawn Williams. Hard to see Bates sitting for any length of time. If he plays well, of course. Iloka goes into 2018 with nine interceptions in 83 games.
--DE Michael Johnson: The veteran right end heads into his 10th NFL season as a highly respected team leader with his blue-collar play. He revived his career last season by often sliding inside to tackle on passing downs. Less looks to be more at this point. Cutting down Johnson's snaps and promoting the more than capable Jordan Willis to starter may very well be in the cards. Willis, a third-round pick last season, was rated the 28th best defensive end by profootballfocus.com on his 360 snaps. Only Pro Bowl left end Carlos Dunlap had higher grades among Bengals ends.
--WR Corey Coleman: The 15th overall pick in the 2016 draft was the first wide receiver selected two years ago. He hasn't lived up to that status. He suffered a broken hand each year, but the disappointment extends beyond that. He hasn't shown the heart it takes to be a top-line receiver. He dropped easy passes last season. He is more likely to be traded than cut, but with a new general manager in the form of John Dorsey, the Browns might be ready to move on from Coleman if he doesn't make a positive impression in OTAs.
--WR Darrius Heyward-Bey: The Steelers have kept the speedy Heyward-Bey on the roster because he is a willing special-teams player, but he hasn't helped much in the passing game. He is coming off a season in which he had just two receptions for 47 yards. If one of the young receivers on the 90-man roster has a strong showing this spring and summer, Heyward-Bey could get released.
--WR Braxton Miller. Miller is a converted former Ohio State quarterback. He is under the gun because of the presence of rookie WR Keke Coutee. Coutee could beat out Miller for the slot receiver job.
--G Jack Mewhort: Mewhort re-signed with Indianapolis in late March after battling knee injuries the past couple of seasons. When healthy, Mewhort is one of the best offensive linemen on the Colts roster. The problem is that he can't seem to stay healthy. Now back with a one-year contract, it will be interesting to see if the former Ohio Stare offensive lineman can stay on the field for an extended amount of time. His presence, along with 2018 draftees Quenton Nelson and Braden Smith, could give Indianapolis some much needed help.
--DE Dante Fowler, Jr.: It's hard to fathom that the third overall pick in the 2015 draft could be out of a job this fall, but the Jaguars gave notice that Fowler may not fit into their plans moving ahead when they declined to pick up the fifth-year option on his contract this spring. The team stated that Fowler has a lot of potential and they were hopeful that he will sign a long-term deal after the 2018 season. But the former University of Florida standout has also had several mis-deeds away from the field and that doesn't set well with Tom Coughlin, the strict executive vice president of football operations for the Jaguars. Fowler's problems have occurred in the offseason the last two years, so the Jaguars will be closely monitoring him from now until the start of training camp.
--OLB Kevin Dodd: Dodd has struggled through most of his first two years, but gets a new lease on life with the coaching change. However, with Brian Orakpo and Derrick Morgan still entrenched as starters and a potential draft steal in Harold Landry coming on board, Dodd could become endangered without a strong preseason. The former second-round pick might be competing with the likes of past late-rounders Aaron Wallace and Josh Carraway just to be the fourth outside linebacker this season.
--WR Jordan Taylor: While Taylor has experience as a rotational backup and is currently the first-team punt returner, he continues to recover from two hip surgeries, and isn't expected to practice until training camp. Taylor stabilized the punt-return game last year, but the Broncos have a slew of options, including Isaiah McKenzie -- if he has solved his fumbling issues -- and rookies like DaeSean Hamilton and undrafted free agent Phillip Lindsay. If one of them emerges, Taylor might lose his return spot before he's back on the field -- and could lose a roster spot along with it.
KANSAS CITY CHIEFS
--LB Frank Zombo: The wily 31-year-old Zombo stands as the team's elder statesman on defense and remains a fundamentally solid and intelligent run defender. But the Chiefs' offseason agenda focused on speed, aggression and youth, and Zombo represents the past more than the future. Justin Houston, Dee Ford and Breeland Speaks appear locks on the outside, which means Zombo may find himself in a battle with Tanoah Kpassagnon for a roster spot.
LOS ANGELES CHARGERS
--DT Corey Liuget: The Chargers haven't been pleased with the play of Liuget and it might catch up with him this year. Liuget will also be suspended the first four games by the NFL. Look for third-round pick Justin Jones to get a shot at his spot. Brandon Mebane is also showing some wear and Jones could get some snaps there as well.
--DT Mario Edwards Jr.: Maybe Edwards comes in and fulfills the potential that made him a second-round draft pick out of Florida State. He's never really blossomed as either a base end or three technique tackle. He'll have plenty of competition as an inside rusher -- a priority offseason issue. Three, the Raiders have second-round draft pick P.J. Hall and fifth-round selection Maurice Hurst, the latter considered a first-round talent with a medical issue involving an irregular heartbeat.