The rise of Martinez was handed by Bernard Leno’s injury.
Arteta speaking during the pre match conference against Aston Villa, he opened up on Martinez departure.
“Obviously, it wasn’t in my plans to sell him,” Arteta said. “But we gave him the chance because he deserved it.
“He performed really, really well but we have to balance the books. We have to make the right choices in the market and obviously, I couldn’t guarantee him to be the number one.
“He’s a very ambitious person, he has been working really hard and he can see now that the opportunity is there. He’s got the opportunity to play with Argentina and when a player asks you to do that I think you have to be open enough and tell him what you think about him.
“If he makes the decision to leave, you should try to support him because he deserves it for the way he has served the club over the years.”