Rookie right tackle James Carpenter injured a knee during one-on-one pass blocking drills Wednesday afternoon and is scheduled to have an MRI tonight. Details will not be available until tomorrow.
Breno Giacomini took over for Carpenter -- the team's first-round draft pick -- and will be the likely successor there if Carpenter is unavailable.
It could be the second huge blow to the young offensive line as rookie guard John Moffitt injured a knee against Baltimore and is out for the rest of the season. Both Moffitt and Carpenter had shown improvement, especially in the rushing game, as back Marshawn Lynch gained more than 100 yards on the ground on successive weeks.