ANN ARBOR, Mich. – Mitch McGary took a deep breath. He wanted to tell the story of why he smoked marijuana one night in March, why the NCAA suspended him for a year because of it and why the confluence of those events is helping lead him to declare for June's NBA draft. It wasn't easy, so he started at the beginning.

For months, McGary had struggled to come to terms with the back injury that limited him to just eight games for the University of Michigan this season, none after mid-December. Less than a year earlier, he helped lead the Wolverines to the 2013 national title game as a star freshman. Now, he was a spectator.

One night in mid-March, with the NCAA tournament about to begin without him, McGary was hanging out with a group of friends at Michigan. He had a few drinks. Someone offered some marijuana – a common occurrence, he said, on campus.

"I always turned it down," McGary told Yahoo Sports. "But that night I didn't."

Less than two weeks later, McGary "dressed" for the Wolverines' Sweet 16 game against Tennessee. He was never going to play, but coach John Beilein thought the sight of him in maize and blue on the sideline, pumping up his teammates, would add some enthusiasm. Michigan eked out a 73-71 win.

Amid the post-victory celebration, an NCAA representative told McGary that he, of all people, had been selected to undergo a random drug test, even though he hadn't played in months.

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A week later, after Michigan was knocked out of the tournament, McGary was contemplating whether to enter the NBA draft or return for his junior season. Coming back would allow him to prove his back was fine and continue enjoying life in Ann Arbor. His play could bolster his NBA draft stock. It was an attractive option.

That's when he was called into a meeting with Beilein and athletic director Dave Brandon. They told him he failed the drug test during the NCAA tournament. Then they informed him of the NCAA's harsh penalty for a first failed test: a minimum one-year suspension from all competition.

If he wanted to play college ball again, it wouldn't be until the 2015-16 season.

"The penalty is a year," McGary said.

No longer was there a debate about his future. McGary will enter the NBA draft by Sunday's deadline, he told Yahoo Sports. He's confident in his future, but says he didn't really have a choice. The NCAA penalty cemented the decision for him.

"It's just with the NCAA and their strict rules, they don't show any mercy," McGary said. "They take their things seriously."

Testing for recreational drugs in college athletic programs is wildly variable, borne of a policy unlike almost any other from the NCAA. It allows schools to set their own standards and merely demands they follow them. The NCAA will test year round for performance enhancers, but "stimulants and street drugs are generally not tested," the NCAA's own "Drug Testing Handbook" states.

Some schools are more lenient. Some, such as Brigham Young, have zero tolerance. Michigan tends to fall on the stricter side, with widespread testing and serious consequences.

McGary said he passed eight drug tests administered by Michigan over his two years in Ann Arbor, including five this year despite his limited play.

"[That's why] this was a surprise," Beilein told Yahoo Sports on Thursday evening. "This is not Mitch McGary. Not the one I know."

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