Rider was arrested in Oakland on Wednesday on a misdemeanor charge of gambling in public. Police said they saw him throwing dice on a street corner with eight to 10 other people, two of whom allegedly had several bags of marijuana.
It was Rider's third brush with the law since June. It was not immediately clear whether the latest arrest would affect a trade in the works that would send the him to the Portland Trail Blazers.
"I think that's just another situation where J.R. was involved with people he shouldn't be associated with," Timberwolves Vice President Kevin McHale said. "I don't think anyone hasn't been in on a card game or thrown some dice. But that's just a bad reflection on him and a bad reflection on us as a franchise."
Rider was booked at the Oakland city jail and released about four hours later, at 6:30 a.m. Wednesday. He is scheduled to appear in court Aug. 19 on the gambling charge. He was already due to be arraigned next Friday on charges from an earlier incident.
Almost three weeks ago, Rider was arrested on misdemeanor charges of possessing marijuana in his car and possessing a cellular phone that had been illegally altered so it could make free calls. Earlier in June, Rider was detained and questioned about an alleged rape, but was never charged.
Police said Rider and three other men were arrested early Wednesday after they received a complaint about a group of people gambling on a street corner in what one officer described as "a high narcotics area" of Oakland.
McHale refused to get into specifics about the rumored trade involving Rider. "It's not a done deal until it's a done deal," he said.
The trade reportedly would send Rider to Portland in exchange for guard James Robinson, forward Bill Curley and a future draft pick.