Cincinnati Bengals offensive guard Kevin Zeitler appears to have re-injured his calf on Sunday.
Zeitler, who has missed three games this season after suffering a calf injury against the Atlanta Falcons, left in the second half on Sunday. He was replaced by Pollak.
The team, announcing the injury, said he was doubtful to return.
Zeitler's first game back was last week against the Indianapolis Colts, where he scored the best Pro Football Focus grade on offense (+1.2) with positive grades in pass protection (allowing one hurry) and run blocking -- he and Boling rated as the team's best run blockers.