TARRYTOWN, N.Y. - Cuttino Mobley, a Philadelphian who played 11 seasons in the NBA, said Thursday he was retiring because of a life-threatening heart condition.

"The specialists I've seen made it clear that my heart condition has gotten worse and I couldn't continue to play professional basketball without putting my health and life in serious danger," Mobley said at a news conference near the New York Knicks' practice facility. "I wanted to continue to play, but I have no choice and I had to step away."

Speculation about Mobley's future had been swirling since he was traded from the Los Angeles Clippers to New York last month. Tests performed by the Knicks uncovered signs of hypertrophic cardiomyopathy.

According to the source, Mobley's previous four teams knew the guard had a heart condition, but may have been unaware of its exact nature. He reportedly signed a waiver that freed each club from liability.

A graduate of Cardinal Dougherty High School and the University of Rhode Island, Mobley, 33, also played with Houston, Sacramento and Orlando.

He has not been on the court since being dealt to the Knicks in a Nov. 21 trade that included three players with Philadelphia connections. Mobley and ex-Villanova star Tim Thomas were sent to New York in exchange for Zach Randolph and Mardy Collins, a Temple product.

Despite their concerns about Mobley's health, the Knicks eventually approved the deal, making it easier for them to clear salary-cap space for an anticipated run at a 2010 free-agent class that is expected to include LeBron James.

Mobley has averaged 16 points a game in a 747-game career.

Contact staff writer Frank Fitzpatrick at 215-854-5068 or ffitzpatrick@phillynews.com