Marcus McGuane has been ruled out for the rest of the season. The on-loan Nottingham Forest midfielder picked up a thigh injury in January but has suffered a setback.
The 22-year-old had recently returned to the training pitches but is required to go on a 12-week recovery programme following recent scans and consultation.
Speaking to the club’s official website, U’s boss Karl Robinson said: “We are gutted for Marcus because he had been doing so well for us and was having a major impact on our season.
“He is a good lad and had settled in here really well off the pitch. On it, he has that same power in midfield that we had last season with Shandon Baptiste, and then with Marcus Browne when we moved him back there.
“We have players with other qualities and we will adapt but all we can do is hope he makes a full and speedy recovery.”
Robinson confirmed on Tuesday ahead of the U’s 1-0 defeat against Portsmouth that the midfielder was in danger of missing the rest of the season.
McGuane has impressed this season, providing four assists in 20 appearances. The 22-year-old also filled an important role in the first half of the season while Cameron Brannagan missed out through injury.
He took to Twitter to thank the supporters for the support.
