Sherman has yet to appear in San Francisco's first two preseason games. He was held out of practice before the Aug. 9 game against the Dallas Cowboys and was eased back into team portions of practice before sitting out Saturday's game against the Houston Texans.
If Sherman can ramp up his activities at practice this week, Shanahan believes he would play in this Saturday's game against the Indianapolis Colts.
"Yes, definitely," Shanahan said on a conference call when asked if Sherman needed to increase activities in practice this week in order to play against the Colts. "But, I think he was close to doing that last week. I know he definitely wanted to. I'm very confident he'll be out there Tuesday practicing, unless some crazy setback happens.
"But right now, it's really just about Richard feels good and he just wants to get his body ready for Week 1."
Sherman began experiencing tightness in his hamstring during practice on Aug. 3. Sherman signed a three-year, $39 million free-agent contract with the 49ers just two days after he was released by the Seattle Seahawks.
The 30-year-old Sherman helped the Seahawks win a Super Bowl title following the 2013 season and led the club back to the championship game the following year.
Sherman was a fifth-round pick (No. 154 overall) out of Stanford in 2011. He has 32 interceptions and 99 passes defensed on his career.