While time seemed to stop as the Celtics processed the devastating reality of franchise centerpiece Jayson Tatum undergoing surgery Tuesday to repair a ruptured Achilles’ tendon, their second-round series against the Knicks is still very much in progress.
The Celtics are in a 3-1 series hole after dropping Game 4 on Monday in Madison Square Garden, shocked not only by the loss of Tatum but by the reality of facing elimination when the plan was to repeat as champions.
Coming back from a 3-1 deficit is a tough road — only 13 teams have done it. Coming back after losing the first two games at home is even tougher — only five teams have done it.
Coming back without Tatum makes a near-impossible task that much more challenging.
The Celtics haven’t had to play many games without Tatum since he arrived in 2017.
Over eight seasons, Tatum has missed just 51 regular-season games.
He had never missed a playoff game until this season when he sat out Game 2 in the first round against the Magic.
When Tatum sat in the regular season, the difference was typically noticeable. The Celtics are 392-193 when Tatum is on the floor and 29-22 when he’s not.
The Celtics, however, built their team around two talented wings in Tatum and Jaylen Brown. They’re the only team in the league with two players signed to supermax contracts. Tatum signed a five-year, $314 million contract last summer. Brown signed a five-year, $304 million deal in 2023.
With Tatum out, the task of leading the team now falls on Brown.
Since Tatum arrived in 2017, Brown has only played 39 games without him.
The Celtics are 22-17 in those games.
It goes without saying that Brown has to do a lot more of the heavy lifting when Tatum is not on the court.
His minutes tick up (from 32.5 per game when he and Tatum are both available to 34.5 when Tatum is out). But his usage rate — the metric that attempts to show how involved a player is in the team’s overall offensive production — jumps from 26.7 to 32.8.
He shoulders all the burden of a heavier responsibility on offense.
He scores more (27.3 points per game without Tatum compared with 20.3 with him).
He shoots more (20.6 field goal attempts without Tatum to 16.0).
He shoots more 3-pointers (7.2 attempts to 5.7) and he gets to the free throw line more (5.8 to 4.1).
He hits the glass more (7.2 rebounds per game without Tatum to 5.6).
He creates more scoring opportunities for teammates (3.9 assists to 2.8) while keeping his turnovers relatively low despite having the ball in his hands more (3.4 turnovers to 2.2).
Still, the Celtics’ winning percentage drops from 66 when Tatum and Brown are both available to 56 percent when Brown is but Tatum is not.
Brown was at a loss for words immediately following Monday’s loss. But he accepted the challenge ahead.
“That’s all that can be said,” Brown said. “Get ready for the next one. Get ready to fight, get ready to come out on our home floor and do what we need to do. That’s the goal, that’s still the goal. We’ve got enough in this locker room, so I believe in my guys.”
The Celtics account for two of the 13 times teams have come back from 3-1 deficits.
In 1968, the Celtics beat the 76ers in Game 1 of the Eastern Division finals, then lost the next three. Bill Russell averaged 27 rebounds over the final three games to help the Celtics climb out of the hole, and Boston went on to win the title that year.
In 1981, the 76ers had the Celtics down, 3-1, again, this time in the conference finals, and rallied.
The only options in front of this year’s Celtics team are to climb out of the 3-1 hole or start facing the realities of a harsh offseason ahead.
Whichever path they take, it will be without Tatum on the floor.
“We’ve still got basketball to play on our home floor,” Brown said. “So we come out and play Celtics basketball.”
Julian Benbow can be reached at julian.benbow@globe.com.