Ron Vlaar a doubt for Aston Villa's trip Stoke

The skipper is unlikely to feature at the Britannia tomorrow, the third game he has missed since limping off in the win at Southampton at the start of the month.

It is not thought to be as serious as the calf injury which plagued the defender this time last season but boss Paul Lambert is unable to put a timeframe on his comeback.

He said: "He is still a major doubt, he will be struggling. It's still early, he hasn't done much so we'll see. Because it's such a tight turnaround (for next week's games against Crystal Palace and Swansea) we don't know if he'll be fit.

"He doesn't feel it's as bad as last time which is important. He has been excellent this year. Losing him is a blow."

But Chris Herd is set to return after missing the 3-2 defeat against Manchester United with a facial injury.

Herd had made his first appearance since New Year's Day in the 2-0 loss at Fulham and was due to face the champions.

Lambert said: "It looks like he's going to be OK. We found out Sunday morning he wasn't fit it was a blow and not the greatest timing but that's what happens."

And the boss confirmed he hopes defender Jores Okore could return before the end of the season as he battles back from a cruciate knee ligament injury.

Lambert added: "He is doing really well, hopefully a bit of luck he will play some part."