However it was confirmed on Friday morning that striker Darren Bent will be sidelined for 10 days with the knee injury he suffered during the Capital One Cup semi-final first-leg defeat at Bradford.
Dutch defender Vlaar has been out of action with a calf injury since sustaining the setback during the goalless draw with Arsenal on November 24, but the summer signing from Feyenoord returned to training on Thursday.
Villa manager Paul Lambert indicated Vlaar will be part of the squad against Southampton if he got through Friday's session at Bodymoor Heath unscathed.
Lambert said: "Ron is a very experienced player. He has been out for the best part of two months and we have certainly missed him.
"We will see how he is but if he comes through okay, he will be part of the squad (on Saturday)."
Bent has had an injury-hit season and suffered his latest setback after being introduced as a substitute at Valley Parade.
Lambert said: "Darren's injury is not so bad but we are looking at maybe 10 days or so out."
Goalkeeper Shay Given also picked up a hamstring injury against the Bantams but first choice Brad Guzan was expected to return against Southampton.