What makes Mack a very valuable prospect, especially for a 3-4 defense, is his versatility to do everything from lining up on the edge of the line of scrimmage as a pass-rusher to dropping back and covering tight ends and running backs.
As he can do both of those things while also being a solid tackler and run defender, he will be able to play multiple spots and roles in any defensive scheme. He can also create confusion for opposing offenses by being able to show rush looks and drop into coverage, or vice versa.
Mack does a great job of consistently playing his assignment, but he also knows how to diagnose a play in space with his eyes. He has very good instincts, while his change-of-direction quickness and pursuit speed allow him to quickly take advantage of those instincts and get in position to make a play.
One example of Mack diagnosing a play and then making a play happen comes on the very last play of the Ohio State cut-up. Mack started out wide off the edge in man-to-man coverage against the tight end, and did a good job of covering him capably over the middle as Buckeyes quarterback Braxton Miller scrambled around looking for a passing option. Eventually, as Miller continues to scramble around in desperation, Mack sees an angle to the quarterback and he uses his speed to get to the quarterback to take him down for another sack.
Mack is a very effective coverage linebacker, as he uses his feet well to stay with his man while he can also switch coverages adeptly. He plays good press coverage and is good with his hands, including in terms of catching the ball or knocking the ball away.
The above play is a good example of Mack’s coverage skill from the Ohio State game. Although subtle, he does a good job of moving out to pick up the tight end in coverage, then has the awareness to switch to the running back getting open toward the left sideline, knowing he had another defender behind him to pick up the tight end where he left off.
As a pass-rusher, Mack appears to have made strides from his junior to senior season. Although he often took advantage of Ohio State’s new right tackle, Taylor Decker, he also brought pressure against redshirt senior left tackle Jack Mewhort, who is considered to be a first- or second-round draft prospect by some prognosticators. While Mack is unlikely to keep up a torrid 2.5 sacks per game pace, he has certainly gotten an early head start on his 2012 eight-sack season.
Specifically, Mack did a very good job as a bull-rusher versus the Buckeyes offensive line. While he is not the most physically-imposing power player, he does a very good job of getting leverage and driving his opponent back.
The following set of screenshots shows a play on which Mack was able to drive Mewhort back toward Miller, bringing heavy pressure to force an incompletion while also drawing Mewhort to commit a holding penalty.
Mack can clearly bring pressure on the quarterback with his bull-rush technique, pursuit speed and rush angles, but pass-rushing may still be the biggest work in progress area of his game. While Mack has shown the ability to beat blockers off the line with a quick first move, he needs to become more consistent with his rush moves and with disengaging from blocks.
If Mack does not win on his first hands move, he does not usually break down a blocker with his hands. His feet and bull-rushing ability can allow him to overcome that, but he needs to become a more complete pass-rusher to be significantly effective in that capacity in the NFL.
Mack sometimes tries to beat his opponents with a spin move, but that move proved entirely ineffective in the season opener. The following screenshots show an example of him getting enveloped by Buckeyes right guard Marcus Hall on an attempt to beat him with a spin move.