Linebacker Sam Acho (right) battles tackle Bradley Sowell in a drill during Tuesday's practice.

Absence makes the heart grow fonder.

Absence apparently also makes a guy want to wallop running back Stepfan Taylor in practice earlier this week, and play well enough to attract the attention of coach Bruce Arians. These are all good things for linebacker Sam Acho, who enters the final year of his rookie contract needing to impress after missing almost all of 2013 with a broken leg.

"I missed a lot of time, and any time you do that, you are eager to get back on the field," Acho said. "I've been eager

to show the coaches what I can do, I am eager just to play football."

Arians has noticed. On a team looking for pass rush while waiting for veteran John Abraham to arrive, Acho has been around the quarterback more than any other player, Arians said. Already Acho is known for a high motor on the field.

Arians wants to see Acho go against Houston Pro Bowl tackle Duane Brown Saturday to truly measure where Acho is right now.

"If you are going against (Acho)," Arians said, "you can't relax."

Arians said he likes his outside linebacker group's competition, and praised their flexibility. Playing the run should not be an issue. But even when Abraham returns – Arians said he is expected next week – all of the linebackers need to work on their multiple pass rush moves.

Acho is used to the questions about how much of a pass rush the Cardinals can generate. He said he believes in the group.

"As a defense, our goal is to be number one in everything," Acho said. "We learned a lot from John, he has more than 100 sacks in his career. He's a guy we learned watching how he rushes, watching his film and seeing what he does."

A ROLE FOR MARTIN

Rookie defensive end Kareem Martin is likely a year away from starting at least, but he's running with the first-unit nickel package – in which the Cardinals utilize four down linemen – as an end and works with the

second unit in the 3-4 base.

Arians likes how explosive Martin has looked. Martin, like tall predecessor Calais Campbell, must continue to work on keeping his pads low. But with his pass rush skills and good first step, "those are things can build off of," Arians said.

Martin did play the three-technique in college on their nickel package, so he isn't altogether unfamiliar with the situation. He has time to learn behind veterans like Campbell and Darnell Dockett.

"It's tough coming in where I was in college, from big man or whatever to bottom of the barrel," Martin said. "But guys like Calais and Dock in front of me, playing seven, eight, 10 years, having those guys teach me will help me going forward."

MENTAL STRIDES FOR WATFORD

Arians has said multiple times that guard Earl Watford has improved in his play, and Watford got the chance to work with the starters Tuesday at left guard as Jonathan Cooper sat out with a sore knee. This is the kind of improvement the Cardinals have been seeking from the 2013 fourth-round draft pick.

"He's had four really good days," Arians said prior to Tuesday's practice. "He keeps getting better and better."

Watford isn't making any bold proclamations about his status. Arians wants him to be able to play both guard spots and it remains unlikely he'll unseat either Cooper or Paul Fanaika with the first unit. But he just wanted to limit his mental mistakes, and "so far, so good."

"As long as I stay off that mental (error) sheet, I'm good to go," Watford said.

There are tangible ways to measure that progress. This year, Watford said, he's only been on it three times. "I'd like to be off it completely," Watford said.

How does it compare to his rookie year?

"I was on it a lot more last year," Watford said.

LINDLEY SITS OUT

Quarterback Ryan Lindley was among the players sitting out Tuesday's practice with an undisclosed injury. He wore a sleeve on his left leg/calf. Cooper, tight end Jake Ballard and tackle Nate Potter all sat out with sore knees, but Arians said all three were expected to practice Wednesday.

Wide receiver John Brown returned to practice after missing three with a hamstring problem, but later in the workout Brown was standing on the side again, his leg wrapped.