Tom Anderson was due to have surgery on Tuesday after breaking a cheekbone during Saturday’s Sky Bet League One game at Rotherham United.
The defender, on loan from Premier League side Burnley, suffered the injury after a collision with goalkeeper Marko Marosi at the AESSEAL New York Stadium.
Midfielder Alfie Beestin is expected to be out for six-to-eight weeks with ankle ligament damage suffered in the same match.