HOUSTON — From beginning to possibly the end, 2013 has not gone Von Miller’s way.

The Broncos’ strongside linebacker left early in the game Sunday against the Houston Texans with a knee injury. He will have an magnetic resonance imaging exam among other tests Monday to determine the extent of the injury.

There is fear Miller suffered an injury to his anterior cruciate ligament, which would end his season. There also is hope tests will reveal his injury won’t be that severe and he might be able to brace up for the playoffs.

“There’s always some concern when your teammate goes down, especially a guy like Von, who’s really starting to click now,” said Broncos cornerback Champ Bailey. “It’s unfortunate, but hopefully it’s something minor and something he can come back from real quick.”

Miller was named to the AFC Pro Bowl team each of his first two seasons after he registered 30 sacks in 31 games. He started this, his third season serving a six-game suspension for violating the league’s drug policy.

When he returned the game didn’t come as easily to him as he had five sacks in nine games before going down early in his 10th game Sunday.

The injury occurred as Miller was engaged with a blocker on the Broncos’ second defensive series. The knee wasn’t hit. It just gave out. Miller told team doctors he had been dealing with looseness in his knee and his condition became aggravated by the sodded turf.

When Miller left the game, he was replaced in the Broncos’ base defense by linebacker Nate Irving. On passing downs, the Broncos employed a defensive end rotation of Robert Ayers, Shaun Phillips and newly signed Jeremy Mincey.

Mike Klis: mklis@denverpost.com or twitter.com/mikeklis