Martinez is expected to be confirmed as a Villa player soon after the club agreed a fee of around £20million – including add-ons – to sign the-28-year-old ahead of Monday’s Premier League opener against Sheffield United.
The Argentine was left out of Arsenal’s squad for Saturday’s win against Fulham as he underwent a medical with Villa, who face Burton Albion in the Carabao Cup on Tuesday evening.
Head coach Dean Smith has been keen to sign a new stopper because Tom Heaton is still recovering from his knee injury.
Heaton, an £8million signing from Burnley last year, suffered ligament damage to his knee against his former side in January and is not expected to return until mid-October.
Martinez ended last season as Arsenal’s regular ‘keeper but saw Leno return from injury to start against Fulham, while Matt Macey was included on the bench as backup.
The Gunners see Brentford’s David Raya as a potential replacement but could find it difficult to prise him away from the Championship club.
Sky Sports are reporting the Bees have ‘warned’ clubs they have no intention of selling Raya or full-back Rico Henry this summer.
However Said Benrahma – the winger linked with both Villa and Arsenal – is available should Brentford receive a significant offer.