Jorge Fossati pointed to the field at AT&T Stadium as a possible cause of the injury that forced Luis Advincula off against Chile.
The Peru captain, 34, had to be substituted with Achilles pain after just 34 minutes of the 0-0 draw on Friday night.
He was replaced by Marcos Lopez.
“Unfortunately, he was in pain,” Fossati said after the game. “We’re hoping it’s nothing more than that, but it was in an area where (the pain can be) unbearable, the Achilles.
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“It came out of nowhere. I realize that this is a grass field today but it’s not normal grass. It’s not grass that’s born, and grows (naturally.) It’s a grass they bring in from elsewhere.
“That can be a bit of a harder surface and it can affect you in that exact place (the Achilles.) I’m not a doctor but I’ve been around football for a few years. I know that Achilles injuries can be caused by that as well.”
The comments follow heavy criticism of the playing surface after Argentina’s opening win over Canada on Friday night.
Head coach Lionel Scaloni said the field in Atlanta was “not good for spectacle” before goalkeeper Emiliano Martinez went further calling the pitch “a disaster”.
Advincula has 119 caps for his country, second only to striker Paolo Guerrero (120) in the current squad.
Peru next faces Canada on Tuesday in Kansas City.
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