Mercilus signed a four-year extension with the Texans, the Houston Chronicle reports. The extension begins in 2016 and is worth $26 million, including $10.8 million guaranteed.

Mercilus appeared in 15 games (13 starts) last season, registering five sacks. He has a total of 18 sacks in three seasons since being selected in the first round of the 2012 draft. He was bound for a reserve role in 2014, but a knee injury to 2014 first-overall pick Jadeveon Clowney gave Mercilus an opportunity for more snaps.

Mercilus (back) is expected to play Sunday against Baltimore, the Texans' official site reports.

Merciulus, who missed last Sunday's game against the Colts, has returned to practice this week and practiced fully Thursday.

Mercilus has been ruled out of Sunday's game with a back injury, the Texans' official site reports.

Mercilus suffered a back injury during last week's game against the Jaguars and was unable to practice this week.

Mercilus is dealing with a back problem and did not practice Thursday, the Houston Chronicle reports.

Mercilus has been the fill-in for Jadeveon Clowney, who has battled a knee injury since Week 1. He's played a lot more football than was originally planned for him back in training camp, so it's quite natural for those injuries to pop up due to playing football over the course of a season.

Mercilus had a team-high nine tackles (five solo) with two sacks and three quarterback hits in Sunday's loss to the Eagles. It was the fifth time in his career Mercilus has had two sacks in a game.

One of the sacks knocked Philadelphia quarterback Nick Foles from the game with a shoulder injury. Mercilus, who has four sacks in the last three weeks, has been filling in for rookie Jadeveon Clowney (knee, then the flu) all season, but has played well enough to earn a large role once Clowney is ready to return.

Mercilus had five tackles and two sacks in Monday night's 30-23 loss to the Steelers.

The quarterback takedowns were the first of the season for Mercilus, who has been filling in for Jadeveon Clowney (knee). Clowney was a game-time decision Monday, so his return is near. That means Mercilus will be back to a rotation role at outside linebacker, but he's shown an ability to get the quarterback in the past. He could be used as a passing-down specialist.

Mercilus will start at outside linebacker in place of the injured Jadeveon Clowney (knee), the Texans' official site reports.

Mercilus, who lost his starting job to Clowney this season, had two quarterback hits in Sunday's win over Washington. He's always been a threat to provide quarterback pressure, having registered 13 sacks in two NFL seasons.

Mercilus had four tackles with a sack and two tackles for a loss in Thursday night's preseason loss to the 49ers.

Mercilus, who lost his starting job to rookie Jadeveon Clowney, had two pretty good games to finish up the preseason. He'll provide good depth at outside linebacker and continues to show an ability to get to the passer.

Mercilus started at outside linebacker in place of the injured Jadeveon Clowney (undisclosed) in Saturday night's preseason win over Denver.

Mercilus played well Saturday, making seven tackles including a sack. He's been a forgotten man as Clowney and Brooks Reed have been the starting outside linebackers, but Mercilus has shown an ability to get to the quarterback. He's registered 13 sacks in his two NFL seasons.

Mercilus is not in the starting lineup for Saturday's preseason game against the Cardinals, the Texans' official site reports.

First-overall pick Jadeveon Clowney and Brooks Reed are listed as starters while Mercilus will be part of the rotation at outside linebacker. Mercilus, who has 13 sacks in first two pro seasons, entered training camp as a potential IDP candidate. Now, it looks like he might not be an every-week starter.

Texans OLB Whitney Mercilus anticipates dropping into coverage more this season.

Mercilus has disappointed as a pass rusher through two NFL seasons, in 2013 grading out as Pro Football Focus' worst outside linebacker in the league. The Texans will turn to Jadeveon Clowney and J.J. Watt as their primary pass rushers this year. "More drops into coverage instead of solely rushing, rushing, rushing," Mercilus said of his role under new DC Romeo Crennel. "Of course I love it. It's definitely showing my versatility and being instinctive on the field."

Despite posting a respectable seven sacks, Texans OLB Whitney Mercilus graded out as the league's worst 3-4 outside linebacker in 2013 at Pro Football Focus.

That's out of 42 qualifiers. Mercilus managed to pressure the quarterback 51 times, but a closer look at his play shows he has deficiencies as a pass rusher. He'll continue to man the weak side this season with Jadeveon Clowney on the strong side, but Mercilus will need to take a step forward in his third season.

Texans 2012 first-round pick Whitney Mercilus will be the team's starting weak-side outside linebacker in his second year.

It's the primary pass-rushing position in Wade Phillips' defense. Trevardo Williams, Sam Montgomery, and Brooks Reed are competing on the other side. Rather than dropping into coverage, Mercilus' responsibility will be to harass quarterbacks. During his rookie season, Mercilus only made four starts but amassed six sacks and two forced fumbles. He's a breakout candidate.

Texans GM Rick Smith anticipates an "exponential leap" for 2012 first-round pick Whitney Mercilus in year two.

With Connor Barwin a free agent and Brooks Reed potentially moving to inside linebacker, Mercilus is likely to be a starter. "He had 6.5 sacks in limited playtime," said Smith. "But when you look at him production per play, it's up there. He adds explosiveness, he's adds pass rush, he adds speed to our defense."

Texans first-round pick Whitney Mercilus racked up two sacks in the team's Week 13 win over the Titans.

After opening the year as a reserve behind Brooks Reed (groin surgery), Mercilus is up to five sacks on the season. Mercilus also recovered a fumble against the Titans and could catch fire down the stretch playing behind LE J.J. Watt. Reed is expected to be sidelined for at least the next 2-3 regular season games.

Texans DC Wade Phillips sees a similarity in how first-round OLB Whitney Mercilus' "light is coming on" to J.J. Watt's development last season.

"Whitney's earned more (playing) time," Phillips said, "so we're going to play him more." After learning from the sidelines early in the season, the No. 26 overall pick has racked up three sacks and two forced fumbles in the past two games.

After watching film of the preseason opener, coach Gary Kubiak says first-round OLB Whitney Mercilus is even better than first believed.

Mercilus' transition from defensive end to outside edge rusher is going smoothly. He racked up three tackles, 1.5 sacks, two hits behind of the line of scrimmage and a quarterback pressure at Carolina. "He's just so fast and so smart," GM Rick Smith said.