AITOR KARANKA will give young Middlesbrough full-back Tomas Kalas every chance to prove his fitness to face Manchester City in the FA Cup.

Kalas had to limp out of Tuesday night’s 2-1 win over Cardiff City after suffering a knock to his ankle and he has been carefully monitored ever since.

While the injury is not thought to be serious, there is a real doubt surrounding his availability for the trip to the Etihad to face the Premier League champions in round three.

"Tomas is having treatment,” said Karanka. “I have to be careful with him because he hasn't played regularly for 18 months and we have to be careful because that position has been a bit of a struggle for us.

“I'll leave it until the last minute for him. If he's fit he's going to play because we don't have another right back. We'll leave him out if he's not 100 per cent fit.”

With Damia Abella (cruciate) and Ryan Fredericks (thigh) already ruled out, and Emilio Nsue on Africa Cup of Nations duty, Karanka's options to fill the right-back role are limited. Rhys Williams is also an absentee who can operate there.

Dean Whitehead, a centre midfielder, and Kenneth Omeruo, a centre-back, are alternatives to fill the void if Kalas fails to make it, but the hope is that Chelsea loanee will make it.

Fredericks, meanwhile, has been allowed to return to Tottenham during his recovery from a thigh problem. The young Spurs defender, who impressed during his time in the Boro side, is close to a return, though.

After a little set-back just after Christmas, Fredericks could be in contention when Championship football returns for Middlesbrough at Brentford on Saturday week.

Karanka said: “Ryan Fredericks has been working on his fitness with Tottenham, their doctor has decided to keep him for one further week and he might be back for the Brentford game.”