Hill, the sixth-year pro who hadn't thrown an NFL pass until this month, has led the 49ers (5-10) to victories over Cincinnati and Tampa Bay in their last two games. He got his first significant NFL action midway through a loss to Minnesota on Dec. 9 when Trent Dilfer, subbing for injured first-stringer Alex Smith, sustained concussion.

Hill took a hard hit late in the first half against the Buccaneers while scrambling, and he missed one play before returning to lead the win. But Hill emerged from the game with back spasms and bruised ribs to go with the already-dislocated index finger on his throwing hand.

The back spasms are Hill's biggest concern heading into the game against the Browns. Nolan said Hill was questionable, but Hill seemed confident he'll recover in time to make his third NFL start.

"Hopefully by the end of the week, we have that under control and we can go out there and play," Hill said. "Certainly because of how long I've waited to play, I want to take advantage of every opportunity."

If Hill can't play, the 49ers will turn over their offense to Chris Weinke, the Heisman Trophy winner and former Carolina quarterback signed as a backup two weeks ago. Weinke handed off on his only snap while Hill recovered from his hard hit against Cincinnati.

Weinke ran the first-team offense in Wednesday's practice.

"Each day I'm here, I become more comfortable," Weinke said. "It's just been a lot of studying the last two weeks."

Nolan confirmed Dilfer is out for the season, though the 49ers haven't placed him on injured reserve. Dilfer was hit hard by Minnesota's Charles Gordon during a scramble, ending the quarterback's 14th season and putting his future in question.

"My intent is to keep playing (next season)," said Dilfer, who signed a long-term contract with San Francisco. "I felt significantly better this weekend, and today I've continued to feel like I've improved. As long as I'm medically fine, my intent is to keep playing."