The Feyenoord striker is in the team as an over-age player with his experience seen as vital to the young squad's chances of making the Olympic podium.
"He went to hospital and he will have a scan today. He has difficulty in walking," De Haan told reporters. "He will definitely miss the next game. We have to be careful about injuries."
The Netherlands were held 0-0 by Nigeria in the opening match and are desperate to beat the USA, who have three points after beating Japan in their opener.
Makaay made his name at Bayern Munich, who he joined from Deportivo La Coruna in 2003, scoring 78 goals for the Bavarian giants. Among that haul was his 10-second strike against Real Madrid in a UEFA Champions League match last year - the fastest goal in Champions League history.