Wrexham keeper Andy Dibble broke his arm in the 6-1 loss at Peterborough and will miss the rest of the season.
Borough striker Calum Willock collided with the 39-year-old Dragons stopper early in the match at London Road.
Dibble was thought to have suffered two breaks and a dislocated shoulder and was taken to a local hospital where he will undergo surgery.
"It's serious and my heart goes out to the lad because he's been brilliant," Wrexham manager Denis Smith said.
"He's out obviously for the rest of the season and at 39 we've got to question with how bad it is what will happen after that.
"He'll be in hospital for two or three days and they will probably operate later today (Saturday)."
Paul Whitfield replaced Dibble after 17 minutes and Wrexham took the lead immediately after that through Chris Llewellyn.
But things went wrong again for the Dragons, as Peterborough marched to a 6-1 win through Willock (2), Clive Platt, Sagi Burton, Andy Clarke and David Farrell.
"I'm not going to criticise individual players, I'd never do that, but there were mistakes made," Smith added.
"I've got injuries and suspensions and certain players were out of their depth."