Shaun Hill won't get the chance to put the finishing touch on his run of success as the San Francisco 49ers' quarterback.

Hill was injured more seriously than reported and won't play in the season finale Sunday at Cleveland, ccoach Mike Nolan said today. Chris Weinke, who was out of football before joining the 49ers three weeks ago, will start.

In addition to back spasms, Hill sustained fractures to the transverse process portions of three vertebrae in his lower back, Nolan said. Transverse processes are small winglike bones emanating from the vertebrae.

Hill was hit in the back at the end of a 2-yard scramble just before halftime Sunday in a 21-19 victory over Tampa Bay. He finished the game, but afterward X-rays revealed the fractures.

The team did not disclose the fractures because Hill didn't want the Browns to target his back if treatments had allowed him to play, Nolan said.

"Shaun asked us to keep it at the spasms," Nolan said. "If he was able to play in the game, he felt it best if it was just kept simple, because obviously, you don't want people going after you."

Hill, who started two games in place of the injured Trent Dilfer, also has been playing with a broken index finger on his passing hand suffered in practice a month ago. Sunday, he also took a hit to the midsection that left him with bruised ribs.

"The timing of this obviously is frustrating," said Hill, who was receiving the first extensive action of his six-year career. "It's kind of a hard thing for me to swallow, but when you can't go, you can't go."

Weinke, 35, last threw a pass in an NFL game a year ago with the Carolina Panthers. He becomes the fourth quarterback to start for the 49ers this season.

"It obviously helped me to be able to take all the reps with the offense this week," Weinke said. "The coaches did a nice job of putting a game plan together to take advantage of the players that we have and also make it a situation where I felt comfortable."

Former UCLA quarterback Drew Olson will serve as Weinke's backup after being promoted from the practice squad. The 49ers made room for Olson by releasing wide receiver LeRon McCoy.

Receiver Arnaz Battle or running back Michael Robinson, both quarterbacks in college, could play in an emergency, Nolan said.

"Hopefully, we'll just stay with Chris the entire game," Nolan said.

The 49ers already have lost Dilfer and Alex Smith, who began the season as the starter, to season-ending injuries. Dilfer suffered a concussion against Minnesota on Dec.9, and Smith has undergone surgery to repair a shoulder separation suffered Sept.30 against Seattle.

Hill's back injury is "very uncomfortable" but will heal in the off-season, Nolan said.

"That's the good news," the coach said. "He'll be as good as new, if not better."

It will get even better for the 49ers if they re-sign Hill, Nolan said. A pending free agent, Hill made a tremendous impression with his accuracy, quick release and playmaking instincts.

"He showed an ability to bring the offense to life," Nolan said. "When Shaun had his opportunity, he stepped up and he did it. We'd like to have him back."

Hill said he would prefer to strike a deal with the 49ers than explore free agency.