Bears quarterback Justin Fields is improving in his return from a dislocated right thumb but remains “week-to-week,” coach Matt Eberflus said Wednesday.

“He’s doing everything he can to progress, and it is progressing.” Eberflus said.

Eberflus ruled him out for Sunday’s Chargers game on Monday, and reiterated then that the Bears still believed Fields would be able to avoid surgery and a trip to injured reserve. An IR stint would keep him out for four more games, minimum.

Undrafted rookie Tyson Bagent will make his second-straight start. He led the Bears to a 30-12 win against the Raiders on Sunday at Soldier Field. Fields wore a small brace on his right hand on the sideline and was able to sign autographs with it on.

Fields hurt his thumb when he was sacked in the third quarter against the Vikings. The Bears need Fields to have the strength to grip a football before he can begin testing his pain tolerance.