Neal Ardley has admitted the injury sustained by Jim O'Brien 'put a dampner' on our Buildbase FA Trophy victory over Chesterfield.
The midfielder hobbled off the field in his first appearance since late September, when he suffered a serious arm injury at Bromley, having sustained a gash to his thigh.
And the manager has confirmed that O'Brien is now facing another lengthy spell on the sidelines.
"It's not good," said Ardley after full-time. "He's got an eight-inch gash right down the middle of his thigh and it's deep.
"Not only has he had several stitches across his thigh, which is bad enough in itself, it looks like there's a tear in the muscle where the stud's gone through as well.
"We've all hyped up how important it is to have him back and this is a real blow.
"It's too early to tell, but I don't think it's going to be weeks. I hope I'm wrong, but that's my gut feeling.
"It's put a dampner on the whole day for me. We've won a game but it doesn't feel like it."
Sam Slocombe was also substituted in the first half and could be set for a spell on the treatment table too.
"Sam just went to catch an innocuous ball and felt his groin as he went to the ground," said Ardley.
"He might have tweaked it - we don't know yet - so it could be a couple of weeks, which isn't good.
"We debated whether to play Sam and there were many reasons we felt we had to, one of which being we'd put effectively a brand-new back four together and that throwing a new keeper in as well would have made it very tough for us to get the victory."
Slocombe's departure paved the way for our keeper coach Jake Kean to make an unlikely debut.
"Jake has decided to go down the coaching path," said Ardley. "He's been brilliant at that for someone so young (28) - he's been great around the place.
"A few years ago he took a bad whack and found it tough from then on to find a club. But he's an outstanding goalkeeper - just look at the clubs he's played for (Blackburn, Norwich, etc) - he's 6ft 4" and understands the game.
"I thought he did very well."
Slocombe's potential absence could open the door for Ross Fitzsimons, who held discussions with Ardley recently.
"I've had a good chat with Ross about his situation," said the boss. "He's obviously disappointed that he's been left out of the team and both physically and mentally he hasn't got himself in the right place.
"We've got to get him back to being hungry and chasing Sam down for the number-one shirt. Hopefully we'll get him champing at the bit now."