Rotherham United boss Paul Warne has suffered another injury blow in his defence with the news that Clark Robertson will be sidelined for the foreseeable future.
The former Blackpool centre-back has failed to shrug off a long-standing groin issue and will need time to recover fully.
Robertson is the second defender Rotherham United have lost to injury in recent weeks, after on-loan Norwich player Sean Raggett was ruled out for two months with an ankle problem.
On the Scot, Warne said: "He is still out for a long period.
"Unfortunately he has a problem with his groin.
“He played through it last year but he has had the same problem and it will take a bit longer.
"We won't rush him back so he will be out for a number of weeks."
Semi Ajayi filled the void left by Robertson and Raggett during Saturday's impressive 1-0 victory over Derby at the AESSEAL New York Stadium.
The 24-year-old is set to partner Richard Wood again when Rotherham make the trip to Villa Park on Tuesday.
Aston Villa, beaten by Fulham in last season's play-off final at Wembley, have endured a mixed start to the season with 10 points from seven matches.
But Warne is aware of the challenge facing the Millers.
"You often get teams that lose in the play-off final having a stuttering start," he said.
"Sometimes it does take a few weeks to get going.
"I have got the utmost respect for Steve Bruce. His managerial career is a joke. You would definitely expect Villa to finish in the top six.
"This league is difficult, obviously, if you play any team when they are on their best you are in massive trouble.
“Hopefully we can catch Villa on an off day."
Villa are favourites to claim the three points on home soil, where they are unbeaten with one win and two draws this term.
Rotherham are looking to end a 28-game winless streak on the road in the Championship, but Warne is confident his side can put up a fight.
"We are the underdog in most games we play," he added.
"It is a pretty amazing place to play. I said to the lads today 'don't get too carried away' when you walk out of the dressing room and see European Cup winner and all that above your head.
"It is an amazing place, an historical place. But I don't think the lads are overawed, we ask them to go out and play with freedom with a massive amount of effort and with a smile on their face.
"Just go out and enjoy your life. If you don't enjoy playing at Villa Park, whatever the scoreline, then you are in the wrong job."