The Boston Celtics will "leave it all out there" as they bid to defend their NBA Championship without injured talisman Jayson Tatum, says Kristaps Porzingis.

Boston could be without Tatum until the 2026-27 season after he underwent surgery to repair a torn right Achilles tendon.

He sustained the injury during the fourth quarter of the Celtics’ Game 4 loss to the New York Knicks on Monday, a defeat that leaves them 3-1 down in their Eastern Conference semifinals series and facing elimination.

The Celtics welcome the Knicks to TD Garden for a do-or-die Game 5 on Wednesday, and though Tatum's injury is a heavy blow, Porzingis says there is no use lamenting his absence.

"It's a part of this sport, part of this game, and we feel for him, of course," Porzingis said.

"But we have to move forward. He doesn't want us to be sad and not play our best basketball. So we're going to go out there and leave it all out there and live with the results."

We love you, @jaytatum0  pic.twitter.com/OOAuOh93Sj

— Boston Celtics (@celtics) May 13, 2025

Head coach Joe Mazzulla added: "Obviously you're always concerned about someone's health, so it's twofold.

"We're concerned about his health, where he's at, and then we're concerned about what we have to do better for Game 5."

Tatum was voted to the All-NBA First Team in each of the previous three seasons and is a likely candidate to be on the 2024-25 First Team.

The third overall draft pick in 2017, Tatum has been among the NBA’s most durable stars, playing 585 career games for the Celtics.

He has averaged 23.6 points, 7.3 rebounds and 3.8 assists over eight seasons.

Tatum averaged 26.8 points, 8.7 rebounds and 6.0 assists this season while shooting 45.2% from the field.