Rebecca Cook / Reuters

Former NBA referee Tim Donaghy, left, discusses a call with Cleveland Cavaliers coach Mike Brown in this April 12, 2006 file photo.

updated 1:27 a.m. ET Aug. 18, 2007

NEW YORK - The referees union maintained Friday that Tim Donaghy is known to be the only referee involved in gambling activities, despite a report that said he was about to provide names of colleagues who also may have violated NBA rules.

The report on 1050 ESPN Radio in New York said Donaghy will provide prosecutors as many as 20 names of other NBA officials and will detail their involvement in some form of gambling, believed to include betting in casinos.

The offenses may not include criminal activity, according to the report, but could violate NBA policy and lead to firings that would decimate the officiating staff. Twenty referees would make up about a third of the league’s roster.

“This incident is an isolated incident and our folks are of the highest integrity and character and we’re open to sitting down with the NBA to discuss measures that help make sure that the integrity of the game is maintained,” said Lamell McMorris, head of the referees union.

“As far as I know, our folks are of the highest character. This situation has been isolated to one individual.”

NBA spokesman Tim Frank said the league had no additional information and would not comment. Commissioner David Stern said last month that he believed no other officials were being investigated for criminal activity, calling Donaghy a “rogue, isolated criminal.”

Donaghy pleaded guilty to two felony charges Wednesday and admitted betting on games he officiated. He also provided inside information to others and faces a maximum of 25 years in prison when he is sentenced Nov. 9 for conspiracy to engage in wire fraud and transmitting betting information through interstate commerce.

According to the antigambling rules given to referees, officials are not allowed to do any kind of betting, except for offseason trips to the race track. Officials are allowed to attend shows at a casino during the offseason, but may not be in the gaming area.

Referees who violate the policy could be fired.

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