The club’s director of football Monchi has talked up Martinez as one of the best in the world.
The Argentina star, a World Cup and two-time Copa America winner, is on international duty for World Cup qualifiers this week.
"He is an important part of the Aston Villa brand, it shows the growth of this club," Monchi told Argentinian media outlets.
"Having the best goalkeeper in the world, totally loved and involved with the day-to-day running of the club. Emi is more than our goalkeeper, he is a reference in the dressing room, the club, for our fans, within the Premier League.
"He is a reference, one of the team captains and an example. In recent years, he won the World Cup, the Copa America, became the best goalkeeper in the world and continues his daily motivation of wanting to be the best individually and as a team member.
"He is a perfect mirror, he did not rest on his laurels, he wants to improve day by day and push the team to grow. He is an easy person to deal with, approachable, who provides solutions within a discussion."