The 23-year-old faces tough competition to be included in Argentina's strikeforce from Barcelona's Lionel Messi and Manchester City's Sergio Aguero.
However, Martinez believes his striker will gain invaluable experience from training alongside such world class players.
"Franco Di Santo is developing into a top footballer," Martinez said. "He's only 23 but he's come on a lot.
"Obviously being called up by Argentina and playing with the likes of Messi and Sergio Aguero is going to do him a lot of good. I could see it coming because I work with him every day. You get a bit biased because you know the player.
"We always believed in Franco. We're just so glad that he's been able to develop into the player that he is today. We hope that he can enjoy the experience and come back to help us."