York's Oli Johnson will not play again this year after going under the knife to repair a groin problem.
The striker, 25, who joined from Oxford in the summer, has been beset with injuries during his brief stint at Bootham Crescent and has managed just one start and six substitute appearances.
And his latest setback will now keep him out for four to five weeks.
"It's been tough with him because, when you sign players, the last thing you want is for them to have injury problems," boss Gary Mills told the York Press.
"He's never really been able to get going for one reason or another, which is very disappointing, but these things happen.
"I'm hoping that, after this, things will settle down and we will get the best out of him and he will be able to help us during the rest of the season."