A part of the Boston Celtics' young core will say goodbye this free agency as forward Jared Sullinger has reportedly reached a deal to be part of the Toronto Raptors. 

The Celtics appeared keen on keeping Sullinger earlier in the off-season, but last week that changed. They rescinded their qualifying offer to him to clear some cap space for the addition of veteran center Al Horford. This made the 24-year-old an unrestricted free agent and signalled the end of his stay in Boston.  

Sullinger tweeted Monday that he is heading to Toronto. According to a report by ESPN, the power forward's new pact with the Raptors is just for a year and will earn him around $6 million. 

The move was a little surprising since Sullinger was one of the key components of the Celtics' young core which helped the franchise again become a playoff contender. But acquiring an elite center like Horford is a huge opportunity so the team had to sacrifice. 

In 81 games (73 starts) during the previous season, Sullinger's fourth year with the C's, he averaged 10.3 points, 8.3 rebounds (career-best), and 2.3 assists per contest. 

Celtics head coach Brad Stevens was all praises for Sullinger and said, according to ESPN's report, "Jared's one of the more talented guys being able to get the ball off the glass, and he's got a beautiful touch and he's a good guy, and so I think he'll do well."

Stevens added that he is "hopeful" the move by the Celtics would benefit Sullinger. 

With the Raptors, Sullinger has a big chance of getting the starting job at the no. 4 spot. He, together with center Jonas Valančiūnas, are expected to lead the team's frontcourt. 

Besides this move, the Raptors are keeping the same core they have last season when they made it to their first ever Eastern Conference Finals.