The Denver Broncos will be without their best tackler of the last two years, as Alex Singleton will be out for the rest of the season due to a torn ACL and has been placed on the injured list by the team.

The team announced the injury on Wednesday from her practice in West Virginia.

Singleton has 31 tackles through three games this season, the most on his team. The 31-year-old has gotten to the quarterback once and stopped a runner behind the line. Singleton also caught an interception in the season opener against the Seahawks.

The Broncos’ third-year linebacker signed after beginning his professional career with the Eagles. He joined Denver on a three-year, $18 million contract, meaning he will hit the market this spring with a knee ailment.

Singleton, a product of Montana State, was a very important part of the Broncos defense this fall after Jewell left in the offseason. Without Singleton, Denver is pretty thin at the linebacker position, as Justin Strnad will now likely start alongside Cody Barton. Kristian Welch is also part of the picture, as is NFL veteran Kwon Alexander, who the team signed to the practice squad earlier in the day.

According to 9 News, Singleton was injured in the first quarter last Sunday but played all 57 defensive snaps and led the team with 10 tackles. Singleton led the team last season and the year before with 177 and 163 tackles, respectively.

The Broncos added young running back Tyler Badie to the active roster earlier in the day, filling the spot vacated by Singleton’s injury list.