Technically, the Boston Celtics traded Grant Williams to the Dallas Mavericks last week. In a very real sense, they essentially let him leave because they had no intention of re-signing him to the four-year, $54 million contract that Dallas offered the restricted free agent. In a perfect world, the team would have likely kept him, but the current NBA Collective Bargaining Agreement has forced Boston to make sacrifices this offseason.

If this were a straight trade, the Celtics would come off as clear losers. In the three-team trade with the Mavericks and the San Antonio Spurs, the Celtics gave up Williams in exchange for two second-round draft picks plus a traded player exception worth around $6.2 million.

It’s not quite a salary dump, mind you. Team president of basketball operations Brad Stevens is among those NBA GMs who have decided that recent rule changes have made second-rounders particularly valuable, essentially when his other option would have been letting Williams walk for free. It also explains why Stevens spent most of the 2023 NBA Draft doing his best Bill Belichick impression by constantly trading down.

Why have they become newly valuable? It’s partly because the NBA’s new CBA includes a second-round exception that will provide teams more flexibility to sign those players, allowing them to avoid using their mid-level exception on draft picks selected after the first round. This could become a competitive advantage since the so-called “second apron” means that teams that go $17.5 million over the luxury tax will surrender their mid-level exceptions.

It’s only by considering that new luxury tax rule that one can fully understand the Celtics’ offseason moves. Last summer, ownership opened up its pocketbooks under the reasonable assumption that they could finally win their first NBA Finals since 2008. Even if owner Wyc Grousbeck and company were inclined to go all-in for a second straight year, the revamped CBA rules have sharply increased the related penalties.

Not that the Celtics would have been inclined to keep the band together even if it hadn’t become much more expensive. When the team lost to the Miami Heat in an extremely noncompetitive Game 7 of the 2023 Eastern Conference Finals, it was essentially inevitable that significant changes were on the horizon.

When it comes to Williams in particular, the writing was on the wall back during the beginning of the playoffs. Williams’s production took a dip in his final year in Boston and he never consistently cracked head coach Joe Mazzulla’s postseason rotation. Given his decreased role on the team, it was hard to see how the Celtics could justify matching the Mavericks’ $54 million offer.

Another factor? The Celtics are hoping to sign Jaylen Brown for what will certainly be a hefty extension. It’s quite possible that, from their perspective, letting Williams walk was necessary for the Celtics to retain the duo of Jayson Tatum and Brown.

For longtime fans, it was tough seeing them part ways with team leader Marcus Smart in exchange for an undeniably talented but injury-prone player who has been tossed around the league like a hot potato. It would, however, be much worse to see them give up on their young core this soon after so much early success. While Brown’s stock has dropped after his Eastern Conference Finals struggles, he’s only 26-years-old and has had significant stretches where he’s been the team’s most consistent player.

Even assuming the team re-signs Brown, Stevens’s vision for the 2023-24 Celtics remains frustratingly opaque, suggesting that there are more moves to come. Right now it’s hard not to examine Boston’s offseason decision-making and echo the thoughts of the Boston Globe’s Chad Finn: intellectually understanding what the Celtics are doing is one thing but “enjoying it is another matter.”