Jared Sullinger has, for most of his three seasons with the Boston Celtics, looked like a steal as the 21st pick of the 2012 draft. But last season he was stagnant, partly because of an injury setback and partly because he didn't live up to the promises of getting in better shape.

GM Danny Ainge even went so far as to publicly announce that Sullinger hadn't reached the goals set for him. In one of his weekly interviews on the local Sportshub morning show "Toucher and Rich" back in February, Ainge said:

"Jared and I have talked a lot about [his conditioning] over the past year. It’s something we take great pride in with our players. Our players have really bought in to our program and a lot of guys – I think every guy has met the goals that they have set in regards to strength and conditioning, and body-fat, and weight, and all the different things our strength coaches do on a regular basis. Jared just hasn’t met his goals.

"He’s not up to the standards that he wants, and is not up to the standards that we think are in his best interests for the long-term health of his career. He’s not up to par to the standards that we feel are necessary to be a consistent winning player and play with great conditioning."

(Quote from Boston.com)

Sullinger, who measures 6'9" in shoes weighed in at 268 lbs at the draft combine in 2012, was expected to enter training camp last year at around 260-265 lbs, but came in 20 lbs overweight, and during the season, he climbed above the 300 lbs mark.

Sullinger worked all summer with John Lucas

So this summer Sullinger took matters into his own hands and joined trainer John Lucas in Houston, Texas to trim down and get in shape for the upcoming pivotal season. Sullinger hasn't been in Boston this summer, so the reports on his progress have come mostly through social media, i.e. tweets from John Lucas and selfies posted by Sullinger. But some of his most recent selfies suggest that he has slimmed down significantly.

It remains to be seen if the weight loss is sustainable, and how it changes his game. It should be a huge bonus for his three-point shooting that he can get off his feet with a lot less weight pulling him down. Better conditioning will help him a lot on both ends of the floor, especially with the defensive plans that coach Brad Stevens employs, which require a lot of movement from the big men.

The downside to the weight loss might be that he no longer can use his body to get in position below the basket, whether it is to post up or to catch a rebound.

Sullinger is headed for restricted free agency

Sullinger's weight issues have made fans - and probably the Celtics organization, too - wonder whether he should stay in Boston beyond his rookie contract.

There have been talks about an extension (which must be signed before October 31st), but according to the Boston Globe, Sullinger's agent David Falk said in February that it would have to be a max extension, which means around $85 million for over five years.

This is not likely to happen for two reasons: First of all Sullinger has to prove that he is worth that much, and secondly the Celtics need cap space to sign eventual impact free agents next summer. So expect him to become a restricted free agent after the season.

The competition in Boston is harder this season

In a best case scenario, Sullinger's post game hasn't suffered significantly, and the weight loss has given him the chance to extend his shooting range to above the arc. In that case, Sullinger could be the Boston Celtics' next All Star-player.

But first Sullinger has to prove that he is the man for the job in Boston. He will see significantly harder competition for playing time this season. Amir Johnson, David Lee and Jordan Mickey can all play at the power forward, and Jonas Jerebko and Kelly Olynyk were both better than Sullinger as stretch big men last season. And in small ball units, even Jae Crowder may play at the four. So when training camp starts, Sullinger might feel like leaving the ashes to step into the fire, if he wants to make most of this season.