Harry Pell is set to miss the remainder of the League Two campaign, due to his hamstring injury.
The U's midfielder pulled up sharply in the first half of the game against his former club Cheltenham Town last month, and was expected to be back in the side after a few weeks.
A few days ahead of his planned return to training though, he suffered a recurrence of the injury and has now been ruled out until the end of the regular League Two season.
He told the official website: "I was devastated when I got the news, I haven't ever had an injury like it and found it almost impossible to get my head round it.
"Everything was going fantastically well for me since I made the move last summer, both personally and as part of the squad, and this hit me hard I've got to admit.
"The Gaffer was great with me once I got the news and was happy for me to have a few days away to clear my head and get used to the situation.
"It was all new to me and I did find it hard that I wouldn't be playing, but I'm back at the training ground now and will play a full part as always, only this time it will be from the stands rather than on the pitch.
"I will do everything I can to encourage the lads in the last seven games, and help push us into the Play-Offs.
"We have all got to stick together now, players, staff and supporters, and get right behind the lads.
"I have a real focus in my head now, I'll be cheering the lads on while I get the hamstring right, and then hopefully I can challenge for a place in the team for the Play-Off games when I'm fit again."