KARL Robinson is challenging Oxford United’s players to prove their worth as the January transfer window draws nearer.

The U’s head coach has criticised certain personnel for some of their displays in a disappointing start to the campaign that has left them 20th in Sky Bet League One.

United have a full 22-man squad of players aged over 21, meaning they may have to sell or loan before they buy.

Robinson said: “Me and the board know exactly what we want.

“We’re not standing here and accepting what’s happened over the last four or five months.

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“We know how strong we can possibly be.

“We knew moving into this season if we found ourselves with some momentum we would have been a real force.

“Without momentum it compounds the negativity very quickly – no-one’s had a break, it’s just been game after game.

“As a football club we say to everybody you need to show some sort of greater performance level.”

United will only be allowed 20 players aged over 21 next season, thanks to the new salary cap that limits Sky Bet League One clubs’ spending to £2.5million per campaign.

And Robinson told BBC Radio Oxford’s Five Minute Fans Forum there would be multiple exits in January.

“Under the new regulations you need to lose to gain,” he said.

“We had incredible funds available for this January but the player trading cap doesn’t allow us to utilise what we probably need.”