Alex Smith’s season is over after the 49ers placed the starting quarterback on injured reserve with a nagging shoulder injury. Smith will undergo season-ending surgery on the shoulder today. He finishes the year with just 914 passing yards with two touchdowns and four interceptions over seven games. San Francisco signed veteran quarterback Chris Weinke to fill the roster spot. Trent Dilfer’s status is in question for Saturday’s game against the Bengals because of a concussion, making the Weinke signing necessary.