The Boston Celtics are heading back to the NBA Finals for the first time since 2010 after beating the Miami Heat in Game 7 on Sunday. While Danny Ainge may not be with the organization anymore, he's still a C's legend and played a massive part in shaping this roster into what it is right now.

But, Ainge believes Brad Stevens is to thank for one huge trade that helped unlock the Celtics‘ current core: Moving Kemba Walker.

Via Heavy's Steve Bulpett:

“I think that, by moving Kemba,” Ainge told Heavy, “it allowed Marcus (Smart), Jaylen (Brown) and Jayson (Tatum) and Robert Williams to really thrive in positional size, with Horford taking up a big responsibility in the front line for Robert and moving Jaylen, Jayson and Marcus to their positions where they can have size advantages.

“It’s just a better fit. I think that is really clear.”

Last summer, Stevens traded Kemba to the Thunder after a tumultuous spell with the Celtics. When he was on the roster, it forced Jayson Tatum to play power forward, Jaylen Brown to occupy small forward, and Marcus Smart at shooting guard. Once Walker was out of the picture, Tatum is now playing SF while Brown and Smart are occupying the C's backcourt. They're all playing in their more natural positions now and the size mismatch has been evident in their dominant play, especially in Tatum's case.

Although the Celtics aren't a huge team, they're bigger than in past years. Plus, most of Boston's squad can defend 1 through 5, which is a massive reason a Finals run has become the reality.

It looks like Brad Stevens made the right decision moving up to the front office. In addition to the Horford trade, Stevens made a key move ahead of the deadline by acquiring Derrick White. He has done a great job running the Celtics so far.