Plymouth Argyle defender David McNamee faces a two-month spell on the sidelines after being forced to have an operation on a fractured cheekbone.
The 28-year-old right-back picked up the injury in an accidental clash of heads during the first half of Tuesday's 1-1 draw against Preston North End.
The Pilgrims' only other recognised right-back, David Gray, is also out of action with an ankle injury.
Gray, who is on loan at Home Park from Manchester United, is receiving treatment at Old Trafford on the injury he suffered in last month's 2-0 defeat at Nottingham Forest.
Argyle boss Paul Sturrock told the Evening Herald: "David Gray should be getting the cast off his ankle in the next couple of days. Then he'll be back down under our supervision.
"Hopefully, he'll be ready for the game against Charlton."