Oxford manager Graham Rix is set to undergo surgery after rupturing his Achilles while training with his squad.
Rix took over at Oxford in March
"There was no-one near me and it was my own fault, but I'm looking at an operation again on it," he said.
"I've done this four times before so I knew what it was immediately. Now I'll have to have a fifth operation on it, which is far from ideal."
Meanwhile, striker Mark Rawle, who has yet to play this season, has returned to training after his groin injury.