Martino spoke yesterday on Argentina radio station La Red and said Messi will play in the Centennial Copa America tournament in the United States, but not the Olympics in Brazil.
"Messi will not go to the Olympic Games," said Martino, who said it was "too much" for the Barcelona star to play in both events and also World Cup qualifiers.
The Centennial Copa America begins June 3, and the Olympics open two months later on Aug. 5.
"We have the Copa America, the Olympic Games, and World Cup qualifiers in September, October and November," Martino said.
Messi is 28 and could have been picked to the Olympic team as one of three over-23 age players. He led Argentina to the gold medal in 2008 at the Beijing Olympics.