The stakes couldn't be higher as the Boston Celtics and Philadelphia 76ers prepare for a historic Game 7 showdown in their NBA playoff series. But the Celtics will have to face their bitter rivals without their star player.

Jayson Tatum has been officially ruled out for the decisive game on Saturday, with an Eastern Conference semi-final berth hanging in the balance. The news came less than two hours before tip-off, despite Tatum being listed as "questionable" on the earlier injury report.

Celtics coach Joe Mazzulla revealed during his pre-game press conference that Tatum was experiencing "discomfort" in his left knee—enough to prompt both the coaching staff and medical team to make the difficult decision to sit him out. The timing is especially painful for Boston, who had built a commanding 3-1 series lead before dropping two straight games to their old rivals.

Tatum's absence is particularly concerning given his recent injury history. The 26-year-old ruptured his right Achilles tendon during last year's playoffs, forcing him to miss the first 62 games of the regular season. He made his season debut on March 6 and had been a key contributor ever since. In Thursday's Game 6 blowout loss to the Sixers, Tatum exited late in the third quarter but downplayed the issue after the game.

This marks the 23rd playoff meeting between these two storied franchises—a rivalry steeped in NBA history. Boston has won the last six postseason clashes, eliminating Sixers star Joel Embiid three times (2018, 2020, and 2023). With Tatum sidelined, the Celtics will need to dig deep to keep that streak alive and advance to the next round.