**FILE** In this Dec. 2, 2012 file photo, San Francisco 49ers quarterback Alex Smith warms up as 49ers head coach Jim Harbaugh, left, stands nearby before the start of an NFL football game against the St. Louis Rams in St. Louis. A person with knowledge of the trade tells The Associated Press that the Kansas City Chiefs have agreed to acquire Smith from San Francisco. The person spoke on condition of anonymity on Wednesday, Feb. 27, 2013, because the trade does not become official until March 12, when the NFL's new business year begins. (AP Photo/Tom Gannam, File)
**FILE** In this Dec. 2, 2012 file photo, San Francisco 49ers quarterback Alex Smith warms up as 49ers head coach Jim Harbaugh, left, stands nearby before the start of an NFL football game against the St. Louis Rams in St. Louis. A person with knowledge of the trade tells The Associated Press that the Kansas City Chiefs have agreed to acquire Smith from San Francisco. The person spoke on condition of anonymity on Wednesday, Feb. 27, 2013, because the trade does not become official until March 12, when the NFL's new business year begins. (AP Photo/Tom Gannam, File)
San Francisco quarterback Alex Smith folds under the pressure of a hit by St. Louis linebacker Jo-Lonn Dunbar on Nov. 11, 2012. Smith later left the game with a concussion.
San Francisco 49ers quarterback Alex Smith against the St. Louis Rams during the first quarter of an NFL football game in San Francisco, Sunday, Nov. 11, 2012. (AP Photo/Marcio Jose Sanchez)
San Francisco 49ers quarterback Alex Smith against the St. Louis Rams during the first quarter of an NFL football game in San Francisco, Sunday, Nov. 11, 2012. (AP Photo/Marcio Jose Sanchez)
San Francisco quarterback Alex Smith (folds under the pressure of a hit by St. Louis linebacker Jo-Lonn Dunbar earlier in the day. Smith and Chicago quarterback Jay Cutler suffered concussions and may not play when the Bears visit the 49ers on Monday night.
San Francisco quarterback Alex Smith folds under the pressure of a hit by St. Louis linebacker Jo-Lonn Dunbar on Nov. 11, 2012. Smith later left the game with a concussion.
San Francisco 49ers quarterback Alex Smith (11) drops back to pass against the Arizona Cardinals during the first half of an NFL football game, Monday, Oct. 29, 2012, in Glendale, Ariz. (AP Photo/Ross D. Franklin)
Green Bay Packers' Clay Matthews (52) reacts after sacking San Francisco 49ers' Alex Smith during the second half of an NFL football game Sunday, Sept. 9, 2012, in Green Bay, Wis. The 49ers won 30-22. (AP Photo/Mike Roemer)
