The shot-stopper was injured in their 3-0 loss to Chelsea, going off at half-time.
Robin Olsen had to come off the bench and may be required to stay in goal for several upcoming games.
Argentinian reporter Gaston Edul stated that Martinez has “a small fracture in one of the fingers of his hand. There is a bone injury. It could be short-term. He asked for the change (for Chelsea) because of the pain in his waist.”
Another account on the X platform, @physioscout, states that such an injury is a two to four-week layoff.
Martinez will be the subject of questions to manager Unai Emery as his team prepare to take on Brentford on Wednesday.
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