Bud Dupree isn't worth removing from the roster, but he currently isn't someone who's earned a second contract. By allowing him to prove himself during his fifth-year, the Steelers gave themselves times. Because making a decision on Dupree right now would be nearly impossible.
It comes down to production. Dupree has played well at times. When he does well in both coverage and rushing the passer, the team sees what they've been looking for since draft night. When he's not playing well, it's almost like having 10 players on the field.
Which leaves Pittsburgh guessing on which Dupree they'll see in 2019.
It also removes any chance of providing a quality contract for both them and the outside linebacker. Essentially leaving one option on the table as to whether or not contract talks can begin early.
After the season, Pittsburgh can decide. If a quality outside linebacker emerges in 2019, the Steelers should at least talk to Dupree about the future. But he needs to prove himself for an entire season before anything concrete can begin.