Celtics trade Kristaps Porzingis to Hawks

The Celtics also are trading away the lesser of their two 2026 second-round picks and acquiring a 2031 second-round pick.

The Celtics ended this season facing a combined salary and luxury tax bill of about $500 million next season, which would have shattered the NBA record. After Tuesday, that figure will be reduced by about $220 million, according to CapSheets.com.

More importantly, Boston will slide under the second salary apron after shedding Porzingis’s $30.8 million salary, easing what would have become significant roster building restrictions such as having a future first-round draft pick frozen, being unable to aggregate salaries in trades, and losing access to the mid-level exception.

With Jayson Tatum likely to miss next season due to the Achilles’ injury he suffered last month, the Celtics will open next season without at least three starters from their 2024 championship team.

These NBA roster-building rules were put in place, in large part, to encourage parity and give all 30 teams a chance to compete. The Celtics’ reconstruction is perhaps the loudest modern example.

Niang, a Methuen native, averaged a career-high 12.1 points per game after the Hawks acquired him from the Cavaliers last February and is a career 39 percent 3-point shooter. But make no mistake, the Celtics completed this deal to shed salary. Niang, 32, will make just $8.2 million next season on an expiring deal.

This trade was possible because the Nets, one of the only teams with notable salary cap space this summer, were able to absorb the $22 million contract of Hawks guard Terance Mann, a Lowell native, in this three-team trade.

When Stevens spoke to reporters after Boston was eliminated from the playoffs by the Knicks last month, he mostly deflected questions about his team’s summer approach, saying its direction would be determined in the subsequent weeks. But the Celtics’ challenging situation was no secret.

“Listen, we’ve been talking about this for years, right?” Stevens said. “The [collective bargaining agreement] has been well-known for years. So there are penalties associated with being at certain levels, and we know that. You just weigh that. You weigh where we are. You weigh everything else then you make those decisions.

“You have to have the clarity of a full season and a full playoffs and a couple good nights of sleep. Then everybody gets in a room and you put your heads together and figure out what’s next.”

Stevens has successfully shed the massive salaries of two players without needing to attach significant assets to find trade partners. Nevertheless, a league source stressed Tuesday night that while the team was pleased with the deals, the mood was somber because the significant contributions and high character of Holiday and Porzingis will be missed.

Boston made its first significant move late Monday night, when it agreed to send Holiday to the Trail Blazers in exchange for 26-year-old shooting guard Anfernee Simons and a pair of future second-round picks, according to league sources.

Simons will make $27.7 million next season in the final year of a four-year, $100 million contract. Holiday, 35, inked a four-year, $135 million extension with the Celtics in April 2024 and will make $32.4 million next season. The Celtics also freed up long-term money, with Simons on an expiring deal and Holiday under contract for three more seasons.

A league source stressed late Monday night that the Celtics acquired Simons because they believe he can bolster the roster, but the source added that the team would “remain engaged on all fronts” in the coming days and weeks. The Porzingis deal certainly reduces the chances that Boston will trade Simons, but anything is possible.

In the summer of 2023, the Celtics acquired Porzingis from the Wizards in a three-team deal in which Marcus Smart, one of the most popular Celtics of the past decade, was sent to the Grizzlies.

The 7-foot-2-inch center almost instantly became a crowd favorite at TD Garden, both with his play and the connection he created with Celtics fans. Just about anytime someone yelled his name, sometimes even in the middle of a game, Porzingis responded with some combination of a smile, wave, or thumbs-up.

He averaged 20.1 points, 7.2 rebounds, and 1.9 blocks per game during the championship season, but his two-year stint in Boston — much like the rest of his career — was also slowed by injuries.

He was sidelined for much of the 2024 playoffs due to a calf strain before triumphantly returning in Game 1 of the NBA Finals against the Mavericks. He put a charge into the crowd when his WWE-style entrance was shown on the Garden video board, then checked in with about seven minutes left in the first quarter and erupted for one of the most dominant stretches in Finals history.

Over the rest of the period, Porzingis had 11 points, 3 rebounds, and 2 blocks, and the Celtics lead swelled from 1 point to 17. They never lost control of the series after that.

But Porzingis injured his left knee in Game 2 and returned for just a victory lap in the clinching Game 5 before undergoing surgery that kept him out for the first 17 games of this past season.

The effects of a March respiratory illness limited him severely over this season’s final three months, too. On Tuesday, Porzingis shared a brief health update on Instagram. He thanked supporters and added, “I’ve been feeling excellent all offseason and looking forward to a healthy and strong European championship tournament with [the Latvian national team].”

Within a few hours of that post, the Celtics had agreed to trade Porzingis to the Hawks, completing Boston’s second trade in as many days.

The Celtics are likely to create a substantial traded player exception when the Porzingis deal is finalized, positioning them to later acquire a player via trade without receiving matching salaries in return. But it is unclear if the exception would even be accessible, because Boston would need to remain under the second apron after using the TPE.

The Celtics are also now about $17 million above the $188 million luxury tax line, potentially creating a pathway to dip below that threshold. That would protect the Celtics from severe repeater tax penalties activated when a team is above the tax line in four of five seasons. Boston has been a taxpayer for the last three years.

Although league-wide free agency talks open Monday night, teams are able to negotiate with their current free agents. The Celtics will have discussions with veteran big men Al Horford and Luke Kornet, who are both unrestricted.

Horford, 39, has not announced whether he intends to play next season, and a league source said Tuesday there is no news to report on that front. If Horford does continue playing, it’ll be worth monitoring whether Tatum’s injury factors into a potential Boston return.

Like Holiday, Horford’s numbers dipped this past season, but he remained a valuable contributor and will likely command at least the $5.7 million taxpayer mid-level exception on the open market.

Kornet, 29, just finished the best season of his career and his sparkling advanced stats have piqued the interest of teams looking for frontcourt upgrades. The Celtics own Kornet’s “Bird Rights,” which would allow them to re-sign him without restriction.

The Celtics also have the 28th and 32nd picks in this week’s draft, which begins with Wednesday’s first round. A league source said more than 50 prospects have visited the Auerbach Center for workouts in recent weeks. When the team drafted Baylor Scheierman in the first round last year, it was obvious that he was unlikely to crack the regular rotation, but as Stevens reconstructs the roster this summer, this year’s picks could find openings.

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.