Over the past three seasons, Kansas City Chiefs outside linebacker Justin Houston has accumulated 40.5 sacks, which ranks second best in the NFL during that time.

Houston has proven to be one of the league's elite defensive players.

In just five short years, Houston has already reached fifth on the franchise's all-time sacks list with 56 career sacks.

There's no questioning Houston's ability to produce when he's on the field, but due to offseason knee surgery, the timeline for when Houston will be back on the field for the Chiefs defense is still up in the air right now.

"I don't know how much he's going to do in (training) camp," Chiefs coach Andy Reid said of Houston back at the end of minicamp in June. "But listen, he's where he needs to be right now. He's a hard worker, so he's bound and determined to get back. I've told you before, when you're around him, you have this optimism.

"I feel optimistic that he's going to be back in a short period of time, but in reality, it's going to take a little bit – and that's okay. You've got other guys that will step in, step up for him at that spot until he gets back. The important thing is he gets back, that he's healthy and that you don't rush it and do something foolish."

SEASON REVIEW

Despite playing in just 11 games last season because of the knee injury, Houston still managed to pick up 30 tackles, 7.5 sacks and 2 interceptions, one of which was returned for a touchdown against the San Diego Chargers in Week 11.

Last season, Houston was named to the Pro Bowl for the fourth time in his five-year career.

Also for the fourth time in his career, Houston was named to the "NFL Top 100" list, which is a countdown of the league's best players as voted on by 700 current players.

He came in at No. 26 this season.

HOW HE FITS

Houston is one of the unquestioned leaders of the Chiefs defense, and his health is one of the major storylines to follow throughout training camp and the early part of the season.

While the defense is obviously better with him on the field, the opportunity is there for players like veteran Tamba Hali and former first-round pick Dee Ford to step up if Houston does miss some time.

In the five regular season games that Houston didn't play last year, the Chiefs defense allowed an average of just 13.4 points per game.

It's therefore possible for this defense to find success without Houston, but it's going to be nice whenever he does find his way back to the field, as he is one of the NFL's elite at his position.