The Boston Celtics sent shock waves through the NBA this past summer when they dealt star point guard Isaiah Thomas [VIDEO] to the Cleveland Cavaliers for budding superstar Kyrie Irving. Both players were pivotal in their respective team's 2016 success and seeing either of them move was quite a surprise.

Several months later, one of the two key pieces in the trade is still talking about it.

Clearly hurt that Boston didn't value him as high as he valued himself, Thomas has let the business end of the game affect his emotions. He feels that despite the potential upside for both teams in a trade like this, the trade [VIDEO]should have never happened.

Injury concerns

Thomas had the best year of his career in 2016, making the All-NBA team and receiving serious consideration as an MVP candidate. His marvelous play propelled the Celtics to the number one seed in the Eastern Conference. The home court advantage against LeBron and Cleveland gave Boston a puncher's chance against the reigning champions.

During the conference finals, however, Thomas was forced out with a hip injury and the team never recovered. It became glaringly obvious after losing Thomas that the Celtics were no match for Cleveland. Even with Thomas playing at superhuman levels, they still would have likely fell short.

After the series, general manager Danny Ainge began looking to the future. Could he trust Thomas' health as he passes 30 and will demand a max contract next summer when he is a free agent? Not counting the injury, the age and impending contract demands were enough to have the team consider other options.

Kyrie demands trade

When Kyrie Irving announced, this summer, his desire to be traded, it almost seemed like fate. With more than enough complimentary pieces and draft picks, surely Ainge could swing a deal. And he did, sending Thomas, two draft picks, Jae Crowder and Ante Zizic in a package that more than met Cleveland's needs.

The options were easy for Ainge to weigh. There was the risk of paying Thomas a max contract and having it ruined by injury, as well as a risk of just letting him walk for nothing. Entering a contract year where he would miss half of it recovering from his hip injury, a trade almost seemed inevitable.

Now, the Celtics have a guy, in Irving, who is younger and signed on for another season after this one at a reasonable rate. He is arguably already better than Thomas and only beginning to enter his prime. There is the risk that he won't resign next season, but his desire to lead a team and the early returns say that he has found a home in Boston.

Thomas has repeatedly gone on record to voice his displeasure at management for dealing him away. He has yet to suit up for his new team as he recovers from a hip injury, which may have some effect on his inability to move on. Once he gets back on the floor, hopefully, he'll start focusing on his current team.