One of the questions facing the San Francisco 49ers this offseason will be who will back up quarterback Colin Kaepernick.Colt McCoy is an unrestricted free agent. Wednesday, the 49ers secured one possibility when they signed McLeod Bethel-Thompson to a future contract.Bethel-Thompson has been in the 49ers' program for the past three months. He was claimed off waivers form Minnesota in October and spent several weeks on the 53-man roster as the third quarterback.