David Zalubowski/Associated Press

A little over a year ago, Kyrie Irving hit one of the most dramatic shots in NBA Finals history to help the Cleveland Cavaliers win an NBA title. Now, he's no longer a member of the Cavs.

Cleveland traded the All-Star guard to the Boston Celtics for a package that includes Isaiah Thomas, Jae Crowder, Ante Zizic and the Brooklyn Nets' 2018 first-round pick, Boston announced Tuesday.

"Kyrie is one of the best scorers in the NBA. He has proven that on the biggest stage, the NBA Finals, the last three years," said Celtics president of basketball operations Danny Ainge in the team release. "He’s been an NBA Champion, an Olympic Gold Medalist, and a four-time All-Star. For all he’s accomplished, we think his best years are ahead of him."

Cavs star LeBron James tweeted his support for Irving:

The Vertical's Shams Charania first reported the news. The Celtics will be traveling to Cleveland to play the Cavaliers on the NBA's opening night on Oct. 17.

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Irving is reportedly "thrilled" to join the Celtics, according to Adrian Wojnarowski of ESPN.com, adding Boston has "strong belief" he will re-sign after his current contract expires. According to ESPN's Jeff Goodman, the Celtics had "significant concern" about Thomas' hip.

While Thomas has been a member of one of the Cavaliers' biggest rivals in recent years, he'll already have a level of chemistry with one of Cleveland's biggest stars. Thomas, a native of Tacoma, Washington, crossed paths with Kevin Love, who grew up in Lake Oswego, Oregon, in AAU ball.

Most expected the Cavaliers to make at least one significant move this offseason to bridge the gap with the Golden State Warriors. Instead, they were unable to acquire either Jimmy Butler or Paul George, and David Griffin's departure compounded the sense of uncertainty swirling in Cleveland.

But even after he described the Cavaliers as being in a "peculiar place," almost nobody expected Irving to engineer a move out of Cleveland. ESPN.com's Brian Windhorst was the first to report of Irving's intentions, writing that he "wants to play in a situation where he can be more of a focal point and that he no longer wants to play alongside LeBron James."

Irving is coming off his best season in the NBA. He averaged a career-high 25.2 points a game, while his 5.8 assists a night were his highest since James arrived in July 2014. Irving's three-point shooting also rebounded following a 2015-16 campaign in which he hit a career-worst 32.1 percent of his attempts. He shot 40.1 percent from beyond the arc in 2016-17.

When Irving has a hot hand, he's nearly unstoppable, which the Boston Celtics learned the hard way when he scored 42 points in Game 4 of the Eastern Conference Finals.

Watching Irving can undoubtedly be frustrating at times nonetheless.

He has never been a good defender, with the Cavs allowing 3.1 more points per 100 possessions when he was on the floor, per NBA.com. Opponents also shot 41.8 percent from three-point territory when matched up against Irving.

Offensively, Irving can be too dependent on isolation situations, and the last two NBA Finals showed why that can be a double-edged sword.

In 2016, Irving had the confidence to go head-to-head against Stephen Curry and hit a go-ahead three-pointer with less than a minute remaining in Game 7.

In 2017, Irving attempted to do something similar with the Cavs down 114-113 inside the final minute of Game 3 against the Warriors. Rather than run an offensive set, Irving went one-on-one with Klay Thompson and settled for a difficult step-back three-pointer that hit the front rim. Cleveland eventually lost 118-113.

Still, Cavs fans accepted the drawbacks to Irving's game because he can single-handedly take over a game with his scoring.

Perhaps more important than what Irving provided Cleveland in the short term, he seemingly would've been one of the team's biggest building blocks in the event James leaves after his contract expires next summer.

In the four years after LeBron left and played for the Miami Heat, the Cavs won 97 games, fewest in the league during that stretch. The franchise had no discernible long-term plan despite having talented young players such as Irving, Tristan Thompson and Dion Waiters on the roster.

Between the departures of Griffin and Irving, Cavaliers fans may begin worrying James is the only thing separating the team from those dark days again.

The stakes are likewise high for Irving. He'll either look foolish for voluntarily eschewing the chance to continue teaming with one of the best players in NBA history, or he'll gain an even bigger respect from inside and outside the league for carving his own path to success.

ESPN.com's Tom Haberstroh showed that at least last year, the Cavs were a far worse team when Irving was playing a lead role:

Celtics general manager Danny Ainge received some criticism after failing to land either Butler or George, especially when it became known what the Chicago Bulls and Indiana Pacers received for the respective All-Stars.

Now, the point of contention surrounding Ainge will be whether Irving represents enough of an upgrade to the Celtics roster that the trade is worth it.

Thomas is essentially the same player as Irving—just three years older. Thomas and Irving are both dynamic offensive players whose defensive struggles can make them liabilities, though Thomas' issues are more pronounced because at 5'9", he's six inches shorter.

Thomas only has one year remaining on his current deal, which was almost certainly a consideration in this trade. The Celtics will have Irving for an extra season, and they'll seemingly have a good chance of re-signing him when his current deal expires.

Still, Butler and George would've addressed what were clear issues with the Celtics roster, whereas Irving is seemingly more of a luxury addition rather than a necessity.

Boston already sacrificed some depth with the Gordon Hayward signing. The team traded Avery Bradley to have enough cap space to give Hayward a max deal. Now, the Celtics are parting with Crowder, another valuable role player and somebody who could match up relatively favorably with James on defense.

Cleveland, meanwhile, comes out as well as it could've given the circumstances, and this trade could ease some fears first-year general manager Koby Altman is in over his head.

In Thomas, the Cavs get an All-Star point guard who enables them to continue contending for an NBA title. Thomas' contract does little to stabilize Cleveland's long-term outlook, though the first-round pick via Brooklyn should.