A regular, quiet August day in the NBA was sent into a tailspin when it was reported that Kyrie Irving had been traded to the Boston Celtics in exchange for Isaiah Thomas, Jae Crowder, Ante Zizic and Brooklyn's unprotected 2018 first-round draft pick.

News broke in late July that Irving had requested a trade from the Cavaliers, but rumors quieted considerably until Tuesday evening, when it was first reported that Irving-for-Thomas talks were heating up. The trade was unexpected, to say the least, so let's grade the trade and take a deeper look at what this means for each team.

Cavaliers grade: A-plus

Cavs reportedly receive: Isaiah Thomas, Jae Crowder, Ante Zizic, Brooklyn's unprotected 2018 first-round draft pick 

The Cavs had no leverage. Everyone knew Irving wanted out, so what was their incentive to offer a blockbuster package to get him? Neither the Bulls nor the Pacers were able to snag a true superstar in deals for their superstars, Jimmy Butler and Paul George. Why should the Cavs be any different?

Somehow, brand new Cavs GM Koby Altman and the front office orchestrated a deal to replace Irving with an All-NBA point guard, a top-of-the-line 3-and-D guy, a young big man with potential and -- perhaps most impressively -- an unprotected first-round pick that well could wind up in the top five of the 2018 draft, if not No. 1.

Before the trade, the question was whether Cleveland would try to replace Kyrie with a "win-now" point guard or build for the future. Now the Cavs have done both in the best possible way, and they did it by taking assets from the one guy in the league -- Celtics president Danny Ainge -- who is notoriously reluctant to part with them.

In the short term, Cleveland is just as equipped to deal with Golden State, if not more so thanks to the two-way ability of Crowder. The new additions could also help coerce LeBron James into staying in Cleveland rather than looking for greener pastures next summer. If LeBron's still not convinced, they could flip Brooklyn's pick for another established star.

But the Cavs also set themselves up for the future. Say next season is an absolute disaster and James decides to take his talents to Los Angeles (for instance) -- the Cavs can let Thomas walk (this is the final year of his contract and he'll likely command a max salary from somewhere), trade whatever remaining pieces they have and rely on Brooklyn's pick to help get them their next franchise cornerstone.

This was not the deal that most expected, and Cleveland did as well as they possibly could have for the present and future of the franchise.

Celtics grade: B

Celtics reportedly receive: Kyrie Irving

Keep one thing in mind as we look at this from Boston's side. Thomas remains, by far, the best bargain in the league at $6.3 million next season. But next summer Thomas figures to command a max or near-max salary. If the Celtics decided they weren't willing to pay him, they essentially just flipped a player who wasn't part of their future plans for Irving -- who is three years younger with an arguably higher ceiling and under team control for two more years. Now the Celtics get two full seasons of Irving on a reasonable contract to see if he's their point guard of the future.

So why only a B?

That pesky Brooklyn pick. Ainge reportedly was unwilling to part with the prized asset for Paul George or Jimmy Butler, so it's curious that he would give it up for Irving. It makes sense from this perspective: The Celtics are stocked at forward. They landed Gordon Hayward in the free agency, drafted Jayson Tatum (who Ainge said they would have taken at No. 1) and they love last year's No. 3 overall pick, Jaylen Brown. Ainge may have been unwilling to part with the Brooklyn pick for a superstar forward, but a young, superstar point guard (given the aforementioned issues with keeping Thomas) was the deal Ainge could not pass up.

The Celtics may have ultimately grown weary of banking on the potential of future picks, so they decided to get an established franchise-level player. We'll have to wait and see how it plays out this season, and in the coming years.