Speaking to reporters on Wednesday (h/t ESPN.com's Jeremy Fowler), Roethlisberger praised the job Conner has done over the Steelers' first five games this season.
"I think James has done some amazing things and deserves to be on the field," Roethlisberger said. "We also know what Le'Veon is and what he brings to the table. I guess we'll cross that bridge if and when it happens."
Roethlisberger added that some of Conner's biggest contributions to the offense are things that won't show up in a box score.
"I think that's what gets lost in what a running back [does] and what he's been doing—pass blocking, picking up the blitz, catching out of the backfield," he said. "I don't want to jinx anything, but he's catching almost everything I'm throwing to him, and he's in the right spot all the time quickly."
Bell has been holding out since the Steelers placed the franchise tag on him in March. The two-time All-Pro was hoping to receive a long-term extension from the team, but the two sides were unable to agree to terms before the July deadline.
Fowler reported on Oct. 1 that Bell intends to return to the Steelers during their bye in Week 7 and will "definitely" play this season.
In Bell's absence, Conner has been Pittsburgh's starting running back in four of the first five games. He ranks seventh in the NFL with 342 rushing yards and ranks third on the team with 28 targets and 22 receptions.
The Steelers rank fifth in the NFL with 28.6 points per game. They are off to a 2-2-1 start heading into Sunday's AFC North showdown against the Cincinnati Bengals.