The photo of Altuve went viral ... showing the Houston Astros star with the ultimate mean mug while standing behind Trump during the ceremony to honor the World Series champs.

But on Tuesday, Altuve spoke with reporters and insisted he was NOT trying to disrespect the President.

"The president was talking ... what do you want me to do?" Altuve said.

"I was just standing there listening. It was an honor to be there. If I didn't want to go, I just wouldn't go."

"I'm behind the president ... probably one of the most important guys in the world. I can't be laughing or doing stupid things while he's talking. I need to listen."