Nathan Baker is set to miss out on Villa's trip to Chelsea - although Yacouba Sylla is back in contention.
Baker came off injured during the first half of Villa's win over Arsenal on Saturday.
The central defender looks set to be out for another week after suffering a twisted ankle at the Emirates.
It means Ciaran Clark - who replaced Baker against the Gunners - or summer signing Jores Okore will come into the line-up at Stamford Bridge.
But Sylla is back in training after injuring his ankle while playing for the U21s against West Ham eight days ago.
"It will maybe take Nathan another week or so to get back," said manager Paul Lambert.
"He is a doubt anyway, so it would be a big ask [for him to be fit]."
Lambert is happy with the competition in his defensive ranks with Clark and Okore vying for the opportunity to partner Ron Vlaar tomorrow night.
"It was something we never really had last year and the competition is important for everybody," added Lambert.
"I thought Ciaran did great for us, coming into a game of that magnitude for Nathan.
"I am delighted with Ciaran and the way he played.
Snap up your '18 Sylla' shirt now.