Deputy executive director Roger Mason is leaving the National Basketball Players Association to become president and commissioner of a new professional basketball league for retired NBA players, The Vertical has learned.

Mason’s departure comes at the conclusion of the union’s negotiations for a new seven-year Collective Bargaining Agreement, which sources say will be ratified Friday with the final tally of player voting due.

Mason, who had a 10-year NBA playing career, has played a sizable part in the NBPA’s transition under executive director Michele Roberts. Mason spearheaded the union’s movement to provide tens of millions of dollars in health care and increased benefits to retired and elderly ex-players. Mason has been a strong conduit to the league stars – as well as the rank-and-file players – in the rebuilding of the players association.

Mason is partnering with film actor and rapper Ice Cube and investors to bring a summertime league called the BIG3 – a three-on-three, half-court basketball league – to cities and venues starting in June.

Plans include eight teams of five players – including an ex-player as coach, as well as a team captain – that’ll tour together from city to city starting in late June.

So far, retired NBA players Kenyon Martin, Stephen Jackson, Jermaine O’Neal, Rashard Lewis and Jason Williams are some of the players committed to play on teams, league officials said.

Ice Cube is the founder of TheBig3 pro basketball league. (Getty Images) More

Hall of Fame guard Gary Payton has agreed to be one of the coaches, league officials said.

Ice Cube is the founder of the new league – along with his longtime business partner and Hollywood CEO Jeff Kwatinetz. Ice Cube told The Vertical that he has been intimately involved in the planning, development and execution of the league’s start-up. Until Mason was recruited to leave the NBPA, Ice Cube had considered taking on the responsibilities of being the BIG3 commissioner, he told The Vertical.

“I thought of this concept as a fan who got sick of seeing his heroes retire and not play anymore,” Ice Cube told The Vertical. “A lot of these guys can still play once they retire – just not the back-to-backs or four games in five nights.

“I started to look at three-on-three basketball and wondered, ‘Why isn’t this played on a pro level?’ It’s the most normal form of basketball. And from there it was like, ‘Yo, why don’t we make this happen?’

“Not only do we get a chance to see these guys keep playing, but we give guys who retired who still got some game – who don’t want to pick up a [microphone] on TV and who don’t want to go overseas to play … some of these guys still want a stage to play on.”

The BIG3’s bet is that the skills and shot-making of players will be compelling without running up and down the floor and the taxing of bodies on a nightly basis. The plan is for the eight teams to be a part of a four-game basketball festival amid musical acts and entertainment. The league would start on June 24 and play for 10 consecutive weeks, touring cities throughout the summer.

The league has been working to secure a television rights deal, league officials said.

“In the summer, people have a basketball hangover from the [NBA] Finals and nothing to watch but some midseason baseball and football players warming up. It sucks, and [the attraction is] to have a league to look forward to, and players they know and want to see ball against each other – grown-man basketball with guys who can still battle.

“I’m totally involved in this. I’ve even neglected a little bit of [my] other work to focus on the infrastructure of this league – how it’s going to be put together – so that the fan and players get the league that they deserve.”

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