The injury turned out to be far worse than the Suns expected when they announced Monday that team doctor Thomas Carter would perform what was termed "diagnostic" surgery.

Stoudemire, who turns 23 next month, signed a five-year, $73 million contract extension last week, the maximum allowed under the NBA's collective bargaining agreement with the players union.

In a news release, the Suns said Carter repaired a joint surface defect roughly one centimeter in diameter on the inside of his left knee.

"The surgery went well and other than the defect that we treated today, Amare's knee is remarkably and structurally healthy," Carter said in the statement released by the team. "Given Amare's age and the nominal size of the location of the defect, I am confident the microfracture procedure performed will allow a healthy and normal return to action."

Considered the cornerstone of the franchise, Stoudemire has improved each year and was a main component of a team that won a league-best 62 games last season.

The 6-foot-10, 245-pound forward was fifth in the NBA in scoring at 26 points per game last season, his third in the league. He averaged 30 points in the playoffs, 37 in the Western Conference finals against Tim Duncan and the San Antonio Spurs.

Stoudemire's loss will leave the Suns with a vastly different team through most of the regular season. The only starters from last season's team will be the NBA's most valuable player, Steve Nash, and All-Star Shawn Marion.

Stoudemire had been bothered by soreness in the knee for several months. He had worked out last week in training camp, but sat out the team's scrimmage and final practice to have the knee examined by three doctors.