Big blow to the Chiefs defense, but at the very least, they were able to re-sign Jaye Howard, who can step into a larger role in the absence of Houston and do fairly well for himself. Best case, Houston runs through rehab like AP did and is ready to start Week One. Worst case, Houston is out the entire season. Odds are likely it's somewhere in between.

It's March. The NFL Draft is still a month away. The season won't start for another six months. And the Kansas City Chiefs' chances to repeat as a playoff team have already taken a serious hit.

Justin Houston, the team's leading pass-rusher for the past four seasons, could miss the season. The Chiefs announced on Tuesday that Houston, 27, underwent surgery on his ACL last month and that his timetable to return ranges from six to 12 months.

So, the best-case scenario sees Houston returning near the beginning of the season. The worst-case scenario sees Houston missing the entire year.

"We're hoping, just because of his work ethic and he's been a fast healer in the past, we're hoping that's not the case, that he'll be able to play this season," said head coach Andy Reid, per The Kansas City Star. "When and where that is, it's just too early to tell."

Houston initially injured his knee -- it was diagnosed as a hyperextension-- in November and missed a chunk of the season. He returned for the playoffs and participated in 44 snaps against the Texans, but rarely saw the field in the Chiefs' divisional playoff game, which they lost to the Patriots. It is not clear when exactly Houston sustained the ACL injury.

In February, orthopedic surgeon James Andrews discovered that Houston's ACL "wasn't functioning," according to Chiefs head athletic trainer Rick Burkholder. Though his ACL wasn't torn, they opted to repair it on Feb. 16.

"Right now, he's in the middle of the process of doing rehabilitation for an ACL injury," Burkholder said. "It was a little tricky because his ACL wasn't torn, but it wasn't functioning the way it should.

"It's too early to tell where he's at right now, but he's on the road to recovery."

The Chiefs' third-round pick in 2011, Houston has recorded 56 sacks in five seasons, which includes his 22-sack campaign in 2014. This past season, Houston managed to rack up 7.5 sacks in 11 regular-season games. So, clearly, the Chiefs, who are coming off an 11-win season, will be challenged to engineer a pass rush without their top pass-rusher.

They did, however, re-sign Tamba Hali (86 sacks since 2006 and 6.5 last year) this offseason and they spent a 2014 first-round selection on Dee Ford, who totaled four sacks last season. The Chiefs will need Ford to experience a breakout season in 2016 and justify his first-round status.