Kevin Durant's departure put a crack in the Oklahoma City Thunder's foundation. But Russell Westbrook has committed himself to securing it. The Thunder announced they had signed Westbrook to an extension on Thursday. 

ESPN's Ramona Shelburne first reported Wednesday that the Thunder and Westbrook agreed to a renegotiated deal that would be signed Thursday. Shelburne added that the three-year renegotiation will be worth a total of $85.7 million.

Westbrook released a statement on the deal, per Royce Young of ESPN:

On Wednesday, Adrian Wojnarowski of The Vertical reported that the two sides were nearing an agreement on a three-year, $85 million contract renegotiation that will pay the point guard $26.5 million next season and $28.5 million during the 2017-18 campaign. Both Shelburne and Wojnarowski noted that the third year will serve as a player option.

According to Wojnarowski, Westbrook could earn $30.6 million in 2018-19 if he doesn't opt out of his deal and test the open market. 

Westbrook, 27, spent his first eight NBA seasons in Oklahoma City. He averaged 23.5 points, 10.4 assists and 7.8 rebounds per game in 2015-16, tying the league record for triple-doubles in a season and making his fifth All-Star team.

The Thunder's decision to sign Westbrook now comes out of necessity. Durant announced his intention to sign with the Golden State Warriors on July 4. In the month since, the Thunder have tried talking Westbrook into renegotiating and extending his contract, per Brian Windhorst of ESPN.com.

When asked if he would reach out to Westbrook to congratulate him, Durant told reporters, "Nah, that's a touchy subject. I'll see once everything dies down." 

At first, Westbrook gave no indication he was willing to play ball. Then, he slowly came around.

Wojnarowski provided insight into Westbrook's thought process on Thursday: 

“The idea of running out to find a super team, that isn’t who he is,” one source close to Westbrook told The Vertical. “He thought, ‘These are my guys here,’ and he wanted to go to battle with them.”

The move makes sense in a short-term, macro sense. Westbrook is functionally adding only one year to his contract. He was set for restricted free agency in 2017; now, it's 2018. According to Wojnarowski, he'll get an $8.7 million boost this season for his troubles.

An additional year also allows Westbrook to reach 10 years of service time, which would open him up for a starting salary of 35 percent of the salary cap (he is currently limited to 30 percent). While that may change under a new collective bargaining agreement, Westbrook maximizes his earning potential while allowing Oklahoma City some breathing room.

He's one of the league's half-dozen best players, a generational athlete who has developed an excellent feel for the game as he's gotten older. While there are still some noticeable warts on his game—he's a below-average shooter and takes far too many risks defensively—he's an asset you pillage the asset farm to get.

The Thunder will have to do some creative maneuvering to make the roster better from here. Victor Oladipo and Steven Adams are going to be restricted free agents next summer. A team could throw max offer sheets at both and leave the Thunder with the prospect of being capped out.

Young reported Thursday that Oklahoma City is "unlikely" to work on extensions for Oladipo, Adams and Andre Roberson, "instead taking advantage of smaller cap holds for 2017 free agency."

With Oladipo and Adams set to enter restricted free agency and both having artificially low cap holds, look for Oklahoma City to be aggressive early in free agency next summer. The circumstances leave the Thunder a finite window to sign an impact player. Don't be surprised if this also means Enes Kanter spends most of this season on the trade block as OKC looks to find Westbrook a co-star.

For the Thunder, it's all about avoiding the final nail in this era's coffin. In 2012, they made the NBA Finals with under-25 stars Durant, Westbrook, James Harden and Serge Ibaka. It seemed they would rule the Western Conference for the foreseeable future.

But a combination of cost-cutting trades and the looming specter of free agency caused the team to systematically fall apart. With Westbrook back for an extra year, GM Sam Presti has a better shot to build a championship-level roster in the near future.