**FILE** San Francisco 49ers quarterback Alex Smith warms up before the start of an NFL football game between the St. Louis Rams and the San Francisco 49ers Sunday, Jan. 1, 2012, in St. Louis. (AP Photo/L.G. Patterson)
March 20, 2012 5:56:53 PM PDT
SAN FRANCISCO --
Quarterback Alex Smith has agreed to a new three-year deal to stay with the San Francisco 49ers, sources confirmed to ESPN.com senior writer John Clayton.