Rookie outside linebacker Sam Acho has developed faster than the Cardinals have a right to expect, and he's been a key factor in the defensive improvement over the past month.
Acho took over the starting right outside linebacker's job a month ago when Joey Porter went out with a knee injury. Porter has yet to return, and he wouldn't play much, if at all, if he had.
Acho has been that good. He has five sacks on the season, all in the last six games.
In the victory over the Rams last week, Acho had two sacks and two forced fumbles.
Acho fell to the fourth round in last spring's draft, primarily because he's a bit short (6-2) and lacks the explosiveness of top linebackers.
But he's smart, and he's picked up the defense much faster than most rookies.
Defensive coordinator Ray Horton gives his players considerable freedom to move and disguise play calls. Young players can't be expected to do that much, but Acho was able to from the time he became a starter.
His intelligence puts him in the right place the vast majority of the time, and Acho's been able to make plays.
His pass-rush ability has been a bit of a surprise. Acho has shown good speed off the edge, something the Cardinals had been missing.
Porter had six sacks in 22 games with the team. Acho has produced considerably more with substantially less playing time.