JUST IN: The undefeated Kansas City Chiefs lose kicker Harrison Butker to knee injury sets to miss the next four games.

Kansas City Chiefs kicker Harrison Butker (29) will undergo left knee surgery and miss the next four games for the undefeated two-time reigning NFL champions, according to multiple reports on Thursday.

The NFL Network and ESPN reported that Butker, a three-time Super Bowl champion with the Chiefs, will be sidelined and placed on injured reserve, ensuring he misses the next four games.

It would mean Butker’s earliest return to the roster would be on December 15th for their game in Cleveland. Butker, who has made 18 of 20 field goal attempts and 21 of 22 extra-point conversion kicks this season, will have arthroscopic surgery on his left knee as he hopes to help the Chiefs capture a third consecutive Super Bowl crown.

He has been crucial for the Chiefs team that has won seven of nine games by seven points or less. Replacing Butker on the Chiefs’ roster, according to the reports, will be kicker Spencer Shrader, who was signed off the practice squad of the New York Jets.

Shrader, 25, will play for his third NFL club of the season. He kicked two field goals for the Jets in a 31-6 loss last Sunday to Arizona and made all three extra-point attempts for Indianapolis in a season-opening loss to Houston in his only NFL contests.

The undefeated Chiefs, who have matched their best-ever start to a season at 9-0, visit 8-2 Buffalo on Sunday. The next few weeks they’ll visit Carolina before heading back to Kansas City for back-to-back divisional games against the Los Vegas Raiders and Los Angeles Chargers.