Philippe Senderos has handed Aston Villa a new injury blow.
The defender has played only two minutes of Premier League football since October when he suffered a calf injury that was then aggravated while he was away on international duty.
He was passed fit to return to work with Tim Sherwood's squad this week, only to hit yet another setback.
Villa boss Sherwood said: "He trained with us, but then had to come out of the session because he felt something.
"I don't know how serious it is, but anytime you are missing any player it is a setback.
"We're hoping that it doesn't mean he is back to square one.
and that it is just a niggle - but normally when you have been out for that period of time you get referred injuries somewhere else. I am hoping it is not too bad."