It’s official, if still a bit hard to believe. Kevin Durant has agreed to join the Golden State Warriors.

Explaining that the decision has been “by far the most challenging few weeks in my professional life,” Durant announced the move Monday in a post on The Players’ Tribune. Per ESPN’s Marc Stein, Durant will sign a a two-year, $54.3 million contract, which includes a player option after the first year, once contracts can be finalized July 7.

Durant averaged 28.2 points, 8.2 rebounds and 5.0 assists last season, and his personal trophy case includes an MVP award (2014), five first-­team all-­NBA nominations and appearances on seven all-­star teams. He has appeared in four Western Conference finals and one NBA Finals (2012), losing in five games to the Miami Heat.

In essence, the Warriors improved on a squad that won an NBA-record 73 games last season while simultaneously weakening their top rival in the Western Conference in the process. But the questions now become: How much more can Durant help Golden State? And where will he have the most impact?

Golden State must cut ties with Harrison Barnes and Andrew Bogut to make room for Durant’s new deal. Restricted free agent Barnes will reportedly head to Dallas after they extended him a max contract, and Andrew Bogut could also find himself in another uniform come the start of the new season.

If those are indeed the casualties from the Durant signing, it is clear the Warriors get an upgrade. According to Mike Beuoy’s win probability metric, which takes all field goal attempts, free throw tries and turnovers for each player and weights them according to the impact those plays had on team win probability, Durant’s 8.0 WPA is second only to Curry (league-leading 10.6 WPA). Barnes and Bogut combined for 3.1 WPA during the regular season. Looked at another way, because each team starts the game with a 50 percent win probability and needs to accumulate an additional 50 percent for the win, Durant’s 8.0 WPA means his contributions are single-handedly responsible for 16 of Oklahoma City’s victories. And that doesn’t count his assists, steals or rebounds. Barnes and Bogut, by comparison, were worth 6.2.

According to wins above replacement, Barnes and Bogut were worth 8.9 WAR, while Durant was worth 17.3.

To sum up, Durant is worth between eight and 10 more wins than the combination of Barnes and Bogut, but that production is possible because Durant uses over 30 percent of the Thunder’s offensive possessions. On Golden State, the only players who use that many of the team’s possessions during the regular season are Curry and Marreese Speights. Klay Thompson and Draymond Green use 26.4 and 18.6 percent, respectively.

I’d suspect that a majority of Durant’s lost possessions would come at the expense of his isolation plays. He ran possession of this type 14.9 percent of the time with Oklahoma City last season, whereas Golden State used that play just 6.3 percent of the time, instead preferring to spot up opponents, cut to the basket or make a play off screens. Durant was used largely as the ballhandler in the pick and roll, scoring .93 points per possession.

With Curry, Thompson, Green and now Durant among the starting five, it is clear the Warriors have an offense that is the envy of every player and front-office executive in the NBA. And they should be able to quell any doubts about their ability to play defense.

During the regular season, the Warriors allowed the fourth-lowest points per 100 possessions (100.9 defensive rating) and the Thunder’s defense — which ranked 12th — improved by two points with Durant on the court. Individually he allowed 0.78 points per possession as the primary defender, holding spot-up shooters to a 31.2 percent field goal percentage.

Where Durant will help the Warriors the most is in the playoffs, especially considering how LeBron James and the Cavaliers were able to hound the Splash Brothers on defense while protecting the paint.

The Warriors set the NBA on fire with their perimeter shooting, but they also scored 44.6 points per game in the paint, including 63.7 percent near the rim. So when Cleveland limited Golden State to 46.8 percent shooting on 26.6 contested shots at the rim per game, it made it nearly impossible for the Warriors to defend their title. Durant converted 70.7 percent of his shots in the restricted area during the regular season and led the league with 1.2 points per possession in the post. That will certainly help any title run against James, wherever he ends up this offseason (though Cleveland looks likely, of course).

We can probably agree that Durant’s addition to the Warriors doesn’t put the team on an 82-win pace, but with the Vegas oddsmakers setting their over/under at 68.5 wins, it is tempting to take the over. Still not convinced? Perhaps Lil B lifting the curse will make you a believer.