He was taken to the locker room for further evaluation, according to the Browns' official Twitter account.
Weeden appeared to hit his head against his offensive lineman, which took him out of the game. Colt McCoy replaced Weeden.
Before he left the game, Weeden was 17 for 26 for 158 yards. He had one touchdown and one interception.
Weeden, 29, was a first-round draft pick out of Oklahoma State in 2012. In his rookie season this year, Weeden has led the Browns to a 2-8 record. He has completed 55 percent of his passes for 2,298 yards and 11 touchdowns. He's thrown 12 interceptions.
McCoy, 25, is in his third year with the Browns. The third-round pick out of Texas in 2010 started 13 games for the Browns last season. He completed 57 percent of his passes for 2,733 yards and 14 touchdowns.