Nobody's place in the starting line-up is safe at Oxford, according to defender Damian Batt.
The full-back has made 27 appearances for the U's this season but admits competition for places is fierce at the Kassam Stadium.
He told BBC Radio Oxford: "You can't take your place for granted and you have to perform because other people will come in and try and take your place.
"There is good competition all around and this is good for the players and the club. All the players here rise to the occasion and want to fight for their place, and people who want to fight get into the 11."
Meanwhile, Oxford's trip to Burton has been moved back 24 hours to Sunday January 29.
The match was originally scheduled to take place on Saturday January 28, but has had to be re-arranged because of Burton's near-neighbour Derby's FA Cup fourth-round clash with Stoke at Pride Park. The game will kick off at 3pm.