Chris Weinke will be the San Francisco 49ers' fourth starting quarterback this season when he replaces injured Shaun Hill on Sunday in Cleveland. Weinke, a former Heisman Trophy winner and Carolina quarterback, signed with the 49ers (5-10) two weeks ago. He will follow Alex Smith, Trent Dilfer and Hill, who won his first two NFL starts in the past two weeks. Hill, a sixth-year pro who hadn't thrown an NFL pass until this month, will miss San Francisco's finale because of back spasms caused by three small fractures resulting from a hard hit in a win last week over Tampa Bay. Dilfer is out for the season because of a concussion, and Smith is on injured reserve due to a separated shoulder.