St. Louis Rams select Aaron Donald No. 13 overall in 2014 NFL draft

Aaron Donald, Pittsburgh (Don Wright/AP) Not long after the St. Louis Rams used the No. 2 overall pick to upgrade their offensive line with Greg Robinson,

Aaron Donald, Pittsburgh (Don Wright/AP)

Not long after the St. Louis Rams used the No. 2 overall pick to upgrade their offensive line with Greg Robinson, they spent pick No. 13 on Aaron Donald, arguably the most disruptive D-lineman in this entire draft.

Already, few teams could match St. Louis' frontline firepower, what with Michael Brockers and Kendall Langford bookended by Robert Quinn and Chris Long off the edge. Donald will step into that Brockers-Langford defensive tackle rotation immediately, and he could soar from the get-go given how potent he has proven himself to be at pressuring the quarterback. Donald also can more than hold his own against the run, meaning St. Louis could view him as a three-down prospect here.

Strengths: Not only experienced at lining up in multiple spots, but productive everywhere. Donald brings a smart, varied rush to the table, which allows him to work with effectiveness from the one-tech spot on out. Most of his victories up front come as result of an explosive first step off the snap. The quickness he flashed for a national audience at the combine was no fluke. Donald also can win with power, if he cannot break through immediately. In that regard, his stature actually can play to his advantage — being a little lower to the ground allows him to get his hands into a blocker’s chest naturally, allowing him to push opponents back.

True to the praise for his work ethic, Donald can stay on the field as a three-down player and rarely downshifts in intensity. He’ll chase the ball whistle to whistle, sideline to sideline, showing enough recognition to keep locked on the right target despite misdirection.

Weaknesses: Can be neutralized when he does not get the first step, with his size occasionally proving problematic against strong guards. Though he more than held his own as a nose tackle at Pittsburgh, his lack of girth makes it difficult to project him there in the pros, potentially limiting his role. Only average arm length plus 6-1 height means that he will not swat many passes at the line if he fails to get home on a rush. May have a tough time if asked to anchor versus the run as a two-gap player.

Grade:A-minus.

Despite being a tad undersized, Donald racked up tackles-for-loss and sacks while moving all over Pittsburgh's line in college. More than that, his coaches praised him for being an absolute workhorse on and off the field, something Jeff Fisher and Les Snead surely took notice of during their draft prep.

He did most of the damage in college on his own, fighting through multiple blockers to make plays. With Quinn and Long drawing heavy attention outside, Donald might be a nightmare for interior lines.

The only slight tick down in the grade comes because St. Louis appears to have other needs that could have been addressed here, most notably at safety. Still, it's hard to criticize the Rams much for taking a potential Defensive Rookie of the Year candidate without having to trade up.

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