NBA

Joint guard: Knicks’ J.R. Smith suspended for marijuana

It’s the risk the Knicks were willing to take when they went all in on J.R. Smith.

Smith will be suspended by the NBA for five games for violating the league’s Anti-Drug Program, the league announced Friday. Smith tested positive for marijuana, according to a source.

The suspension is without pay and starts only when he is fit to play, though it’s unclear who would make that determination. Smith is rehabbing from mid-July knee surgery and may not be ready for the season opener on Oct. 30, based on his timetable of 12-to-16 weeks.

Smith signed a three-year, $18 million free-agent contract this offseason — with an opt-out after Year 2. The mercurial swingman often has been linked with late-night carousing and was called out by pop star Rihanna for going out too much during his woeful playoff slump last spring. She tweeted Smith was “hungover from clubbing every night’’ before she took down the post.

According to the NBA’s drug policy, a player usually is not suspended until he fails three tests for marijuana. The drug program is so ironclad teams aren’t informed when a player fails a drug test unless it results in a suspension.

Marijuana is not classified as a “drug of abuse’’ in the policy. Violations with drugs of abuse result in suspensions of two years.

The NBA’s marijuana policy reads: “If a player tests positive for marijuana, or if he is convicted of, or pleads guilty to, the use or possession of marijuana, he will be required to submit to treatment, counseling, and aftercare testing in the program. A second violation will result in a $25,000 fine, and any subsequent violations will result in a suspension that is 5 games longer than the player’s immediately-preceding marijuana suspension.’’

Players are subject to four random tests during the NBA season and also two random tests each offseason, the policy states.

Smith is coming off his career season in which he scored 18.1 points per game and won the Sixth Man Award, but his off-the-court baggage prevented him from getting a whopping offer in free agency. The Knicks gave him the maximum yearly salary they could under the early-Bird rights rules, but Smith nixed going the full four years so he can re-enter free agency sooner. Smith stands to lose $252,000 in salary during the suspension.

Knicks general manager Glen Grunwald declined comment.

It’s been a wild offseason for Smith, who postponed his surgery until July, though it appeared clear he needed an operation to repair a chipped patella tendon and torn meniscus that hampered him during the Knicks’ second-round series against the Pacers. He was suspended for one playoff game for elbowing Jason Terry of the Celtics in the first round.

Smith took some heat for showing up to an offseason event with blond hair, then admitted coach Mike Woodson made him dye it back. He was also linked to driving a $450,000 armored truck to a Manhattan restaurant last month, but he denied it to The Post last week, saying he was driving a Bentley and the armored truck was his friend’s vehicle.

During a golf charity event last Saturday, Smith said he was “100 percent sure’’ the Knicks would bring home a title. He also said there would be “consequences” for Paul Pierce’s remarks about the Nets taking over the city.

During a question-and-answer session with youth golfers, Smith was asked whether he regretted jumping to the pros immediately after high school in New Jersey, rather than attending North Carolina.

“I missed the college experience,” Smith said. “I grew up a little too fast. Technically, I was a man at 17. There were different situations that had I gone to college, I would have known what to do. But at age 17, I was doing what I wanted to do — playing against NBA guys.’’