For anyone who scoffed at the news that Hasheem Thabeet is plotting an NBA comeback, a trainer who counts Kevin Durant and DeMarcus Cousins among his past clients has a reality check to offer.

"He should be on a roster sometime next year," Keith Williams said.

For the last several months, Williams has guided the 7-foot-3 Thabeet through a training regimen that has brought the 32-year-old former No. 2 pick of the Memphis Grizzlies back onto the radar of several NBA franchises ahead of next month's NBA summer leagues in Salt Lake City and Las Vegas.

“I think summer league is a foregone conclusion," Williams said, echoing the belief of Thabeet's agent, Jerry Dianis, that Thabeet will have multiple options if he wishes to play on an NBA summer league team.

Williams is putting Thabeet through 1-2 workouts per day and is "trying to change the narrative" on Thabeet, who last played in an NBA game five years ago.

"I think a lot of it is the NBA puts you in a certain box sometimes," Williams said. "It can be hard to get out of it. Once they deem you to be a certain type of player, it’s hard. It’s difficult for them to see you any other way. I think that’s the biggest thing he’s working against.”

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Fair or not, Thabeet was pegged as a flashy dresser lacking the drive to fulfill the potential that brought the Grizzlies to select him ahead of Stephen Curry in the 2009 draft.

"His swag didn’t match up to the basketball," his former Memphis teammate Tony Allen told "The Chris Vernon Show" in January. "He thought that was more important. I just got out of his way. I knew I couldn’t get to him."

Thabeet told the Commercial Appeal that it wasn't until he played a key bench role for a 60-win Thunder team in the 2012-13 season that he truly learned how to be a professional.

In 66 games that year, Thabeet averaged 2.8 blocks per 36 minutes, which was seventh among players who appeared in at least 60 games. But after that season, his opportunities in the league dried up as more versatility became required of big men.

Now, Williams is determined to help prove the narrative on Thabeet from a decade ago no longer applies and that his game translates to the modern NBA.

“He’s been mentally focused on exactly what he has to do," Williams said. "I think ultimately that will pay off."

That includes the agility required to defend the pick and roll and the offensive range required to keep opposing defenses honest.

"He’s going to surprise people because he’s shooting it a lot better than he ever has," Williams said. "That’s what’s going to throw people off the most is that he can be a floor spacer. Most importantly, he’ll have the energy to jump out on a pick and roll, kind of control the ball-handlers enough so that they can’t just rush out on him. Then he’ll be able to get back and get the rebound or a blocked shot."

One comparison Williams offered for Thabeet is Rockets center Clint Capela.

"I think he can be that type," Williams said. "Obviously, he’s older and more savvy. But he can play that type of role for a team."

Reach Grizzlies beat writer David Cobb at david.cobb@commercialappeal.com or on Twitter @DavidWCobb.

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