The surgery to remove bone spurs from Marbury's left ankle was expected to be a 30-minute procedure, according to the New York Post. But a source told the newspaper it turned out to be much more complicated and took Dr. William Hamilton two hours to perform the operation.
Marbury had originally said he would try to return this season. He had the same surgery when he played in Phoenix and was sidelined for most of the offseason.
The Knicks -- who have made it clear the surgery was Marbury's choice -- said it was successful, and head coach Isiah Thomas expressed hope Marbury would return.
"We still hope that it's indefinite. We haven't given up on him for the season yet," Thomas said after the Knicks' 99-98 win over the Bucks Saturday night. "Hopefully we'll have him back."
Marbury had missed 17 games before his surgery, mostly after his father died in December, and was averaging a career-low 13.9 points.
The Associated Press contributed to this report.