NEW YORK — Disgraced NBA referee Tim Donaghy was a compulsive gambler whose road to professional and personal ruin began on the golf course, where he bet up to $500 a hole, according to an evaluation filed on the eve of his sentencing.

"In short, he could not stop himself from gambling," wrote Stephen Block, a longtime New York-based gambling treatment counselor.

Donaghy, 41, faces up to 33 months in prison at his sentencing Tuesday in federal court in Brooklyn after pleading guilty last year to taking thousands of dollars in payoffs from a professional gambler for inside betting tips. The evaluation was filed by his defense attorney, John Lauro, in a bid for leniency.

"In my professional opinion, Mr. Donaghy would never have committed these offenses if he was not a pathological gambler," Block concluded.

Block, who interviewed Donaghy in January, traced his problem to 1994, when he started betting up to $500 a hole and playing card games at various golf clubs in his home state of Pennsylvania. He was introduced to the world of professional sports gambling, where he bet on football and baseball before becoming embroiled in the NBA scheme.

"His gambling history demonstrates the need to gamble to fulfill the underlying need for 'action,'" Block said. "He continued to gamble despite the consequences and the fear of disclosure of his activities."

Donaghy, like many gambling addicts, successfully concealed his problem for years, Block wrote.

"Mr. Donaghy's ability to accurately referee games has no connection to his compulsive gambling condition," he said. "It is very common for the employers of pathological gamblers to never notice a decrease in job performance."

The criminal case ended Donaghy's 13-year career with the NBA. Also, his wife of 12 years has filed for divorce.

"His gambling has caused devastation in many areas of his life," said the report, adding that "continued professional treatment would benefit Mr. Donaghy in his recovery."

Prosecutors declined comment on Monday.