The Boston Celtics reported Tuesday that All-Star forward Jayson Tatum underwent surgery to repair a ruptured Achilles tendon in his right leg. The injury occurred at the end of the fourth quarter of Monday’s Game 4 loss to the New York Knicks.

The surgery was successful, the team reported, but Tatum’s return is uncertain.

Tatum was in the process of one of the most complete playoff games of his career, with 42 points on 16-of-28 shooting, when he collapsed to the court in what seemed like agony with just three minutes left in the game. He had to be helped off the court and couldn’t put any weight on his injured leg.

Though the Celtics now find themselves on the brink of elimination, most of the postgame attention was on Tatum’s health.

“At this point, I’m just concerned about Jayson,” veteran center Al Horford said in the locker room. “That’s the most important thing to me. The game stuff—we’ll deal with it. But I’m just hoping he’s OK.”

A Pillar of the Celtics Franchise

Since he was drafted third overall in 2017, Tatum has become one of the most consistent stars in the NBA. He recently turned 27 and will be selected to his fourth consecutive All-NBA First Team—a distinction achieved by just 43 players in Celtics history.

Monday’s 42-point performance was the fifth instance Tatum has scored at least 40 points in a playoff contest, tying Celtics icons Larry Bird and John Havlicek for franchise history.

Tatum led the Celtics in points, rebounds, and assists last season’s championship year, when the Celtics won their record 18th NBA championship. He has also played more games than any other player in the league since joining the league and has represented Team USA in the Tokyo and Paris Olympics.

According to ESPN Stats & Info, Tatum trails only LeBron James in career playoff points scored before the age of 28.

Now, the Celtics are coping with the unimaginable—surviving the rest of the playoffs, and maybe next season, without their franchise cornerstone.

A Team Seeking Answers

This is a harsh setback for Boston, which was looking to make its fourth straight Eastern Conference Finals appearance and sixth in eight years. To rub salt in the wound, the Celtics have now missed double-digit leads in three games this series, including a 14-point lead in Monday’s defeat.

“They occur,” Celtics center Kristaps Porzingis said postgame. “We all felt sorry for him then, but we have to just keep going. It’s the nature of the game—it’s tough, and it’s not easy to watch and not easy to swallow. But it is what it is, and we have to go on with what we have.”

As teammates and fans alike catch their breath, this much is clear: Jayson Tatum’s defeat leaves a huge void—not just in the playoffs hopes of Boston, but in the team’s heart as well.