Coach Kyle Shanahan said Thursday that Allen will be San Francisco's backup quarterback behind Brock Purdy for Monday night's Week 1 game against the Jets, Eric Branch of the San Francisco Chronicle reports.
Allen won the gig over fellow veteran Joshua Dobbs. Allen completed 19 of 30 passes for 194 scoreless yards and no interceptions during limited preseason work. The 32-year-old has made nine NFL starts since entering the league as a 2016 sixth-round pick.