Messi needed out wide - Martino
Martino's side face Croatia on Wednesday before a clash against Portugal six days later, with Juventus star Carlos Tevez set to make his international return.
The World Cup runners-up have Messi, Tevez, Sergio Aguero and Gonzalo Higuain in their squad.
Martino said it could mean Barcelona star and Golden Ball winner Messi plays out on the wing and it was unlikely the quartet would all be on the pitch at once.
"We have decided that Messi has to play on the right wing otherwise we would have, given how they play in their teams, almost a fourth number nine," he said.
"I also know Higuain doesn't play in the same way as Aguero does, or Tevez does.
"But, at the end of the day in a system like ours not everybody has to be a number nine nor have the qualities to move to the wing.
"As I said before except in specific cases and certain moments of a match or certain moment of a decisive tournament, it will be pretty difficult to see all of them or most of them at least at the beginning of a game."
Martino plans to rotate his squad for their upcoming friendlies, eager to see as many players as possible ahead of next year's Copa America.
"Actually, in these friendlies where we'll play two games, the idea will be to watch as many players as we can, from the beginning of the match or during the game," he said.
"Maybe building different line-ups and we will follow this idea as we did in the last tour [of Asia]. And we will confirm the line-up after the training session."