"#49ers LB Dre Greenlaw (Achilles) is now officially out for the game," NFL Network's Tom Pelissero wrote on his X account.
Greenlaw was carted off the field during the second quarter of Super Bowl LVIII. The linebacker attempted to run back onto the field after the Niners' punt with 9:26 remaining before he appeared to fall while taking a step forward.
Greenlaw was seen in tears as he was carted off the field during the CBS live broadcast. The 26-year-old recorded three tackles prior to being ruled out of the game and replaced by Oren Burks.
"He's had an outstanding year, that's a huge loss," CBS analyst Tony Romo said when Greenlaw was initially taken to the injury tent.
Greenlaw had previously missed the Niners' Week 18 regular season game against the Los Angeles Rams due to Achilles tendonitis and was reported to still be dealing with the injury prior to the team's NFC Divisional Round win against the Green Bay Packers on January 20.
Greenlaw recorded 120 tackles, 1.5 sacks and four pass deflections during the regular season and 15 tackles, and two pass deflections during two playoff games.