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Martinez was due to attempt training on Tuesday afternoon and could play against Brentford on Wednesday night, depending on how much pain he is feeling.
But with the injury relatively minor and Villa facing a hectic fixture list in the coming weeks, Emery has no concerns about handing Robin Olsen a rare start should his No.1 be in discomfort.
Olsen made his first appearance of the season when he came off the bench to replace Martinez in Sunday’s 3-0 defeat at Chelsea.
Emery said: “He (Olsen) played a very good match for 45 minutes and we have to believe and try to be confident with every player.
“On Sunday he played a fantastic match in the second half. If Emi Martinez is not available, of course he is an important player for us but we are going to play Robin Olsen.”
Reports in Argentina late on Monday claimed Martinez had suffered a full fracture of his finger but the injury is not so serious.
Asked what will determine whether he plays against the Bees, Emery said: “How he is feeling.
“He doesn’t have a fracture. That is important. It is only a fissure and his progression today and yesterday has been, at the beginning, going well.
“But he has to train with us and see how he is going to feel. In case the pain he had means he has to avoid training he won’t be ready for tomorrow.”
Midfielder Amadou Onana remains out with a foot injury, while Emery expects Jacob Ramsey to miss at least another fortnight with a hamstring problem sustained in last month’s defeat at Liverpool.
Villa head into Wednesday’s match looking to snap a run of eight matches without a win which has seen them fall into the Premier League’s bottom half.
“In the league we are not being consistent and this is my challenge, how we can recover our confidence, our power and our strong structure playing at home,” said Emery.