Stoudemire injured the knee earlier this month and will be out for two to three weeks, which rules him out for the Knicks' opener against the Brooklyn Nets on November 1.
The six-times All Star has headed back to New York for further evaluation.
Stoudemire, 29, has had a string of injuries during his career, including surgery on the same left knee back in 2005.
"It's sad right now. It seems like he can't catch a break," team-mate Carmelo Anthony told the team's website. "Hopefully it's nothing too serious."
Stoudemire averaged 17.5 points per game last season, his first season scoring below 20 since his injury shortened 2005-2006 campaign.