LAS VEGAS – Last summer Jared Sullinger embarked on a personal improvement journey that turned out to be a waste of time.

He spent that time in intensive workouts with John Lucas, lost weight, improved his conditioning, and let it all unravel during the season. According to a league source, his weight soared over 300 pounds.

It amounted to self-destructive behavior in a contract year, and now that the Celtics power forward has joined Toronto on a one-year, $6 million contract, he’s back on the proving ground. To hear Sullinger’s agent tell it, the 24-year-old power forward admits to the error of his ways.

“Jared understands that if he had controlled his situation better, his options would have been better,” David Falk said Tuesday.

Though Sullinger’s weight gain played a major role in the Celtics’ decision to rescind his $4.4 million qualifying offer, teams still recognize his unusual skill for a big man. According to Falk, six teams were interested in signing Sullinger, including one that offered much better money. Sullinger chose Toronto, Falk said, because of the opportunity to play an important role.

The gap was created when Bismack Boyombo cashed in on a career year by signing a four-year, $70-million deal with Orlando – a contract identical to the money and years Evan Turner is about to receive from Portland.

But Falk said his client has chosen to bet on himself, figuring that next year’s equally cash-heavy free agent market will offer a substantial payday, provided Sullinger proves himself with the Raptors.

“What happened the last two weeks has been major wake-up call for him,” said Falk. “He’s in the gym twice a day. He knows what he has to do.”

Falk has encouraged Sullinger to look at the future, and to consider the deals that less talented (but fitter) players have signed this summer. According to the agent, opportunity and the quality of the Raptors team took precedence over better money elsewhere.

“I’ve always advised my clients not to be a slave to money, and Jared had a deal for twice the money from another team, but it wouldn’t have been as qualitative a situation as going to Toronto,” said Falk, who declined to name any of the other teams that came calling. “We turned down an offer of over $10 million. But my feeling is that in this market, when you look at the deals that players like Bismack Biyombo signed (four years, $70 million with Orlando), Jared is a $20 million player because of his skill. He was Boston’s best big last year – a regular double-double guy.

“But first he has to show people,” he said. “As my dad used to say, (betting on yourself) is the ultimate acid test.”

Or, in this case, a food test. Bad eating put Sullinger in this situation. The Celtics, in signing Al Horford, would have had an overloaded front court had they brought back Sullinger. His weight simply made the decision easy for Celtics management.

“Jared acknowledges that he put himself in this situation, and he has to get himself out of it,” said Falk, who said that there is no bitterness towards the Celtics.

“None of the blame falls on Brad (Stevens) and Danny (Ainge),” said Falk. “Jared acknowledges that. People in Boston were very supportive of him. Bryan Doo (Celtics strength coach) did a tremendous job working with.

“Brad Stevens is a terrific coach,” he said. “Unfortunately Jared and I couldn’t do what we had hoped we could have done this summer, but now we’re looking forward to next year. Jared is an enormously talented player. He can shoot threes and he’s a great rebounder.

“I hope a change of scenery is conducive to helping him change things.”