I believe the benefit of Aldon Smith starting at OLB is often overlooked. Last season, Aldon Smith put on a clinic as a situational pass rusher. Having 14 sacks in his rookie season after a significant change from 4-3 defensive end to a 3-4 outside linebacker has put him on the radar of opposing teams.
The one aspect of Aldon Smith that everyone covers is the impressive number of sacks by a situational player, and I believe this has led to the misconception that the reason he was a situational player was that he is only a one-trick pony. Those who consistently follow 49ers football may recall the notion that they bring him in only to "pin his ears back and go full speed after the quarterback."
The reason that Aldon Smith was used as a situational player last year was to make sure his youth and heavy pursuit were not used against him. A brief comparison of Ahmad Brooks, Parys Haralson and Aldon Smith's statistics shows that Smith is making tackles in run support, as is Haralson, even in limited involvement in running downs.
|Player ||Games ||Starts ||Comb Tackles ||Solo Tackles ||Sacks ||Forced Fumbles ||Passes Defensed ||Saf.
|A. Brooks ||16 ||16 ||50 ||35 ||7 ||3 ||3 ||0
|P. Haralson ||16 ||16 ||30 ||24 ||2 ||3 ||0 ||0
|A. Smith ||16 ||0 ||37 ||31 ||14 ||2 ||4 ||1
The biggest problem that opposing teams are going to have with Smith is the number of different ways he not just defeats, but dominates offensive linemen (all of which are on display in the above video). He has the strength to flat out overpower, the speed to go around or stunt inside and the moves and awareness to move the offensive tackle where he wants him, disengage and then get the quarterback. He also has the speed to chase down and beat quarterbacks with elite athleticism before they reach the line of scrimmage.
Aldon was described by his teammates as a humble but hungry player eager to learn; however, he was drafted based on his ambition and hunger. He told 49ers head coach Jim Harbaugh that he sees himself able to achieve 25-30 sacks in a season, and his rookie year showed nothing to indicate that goal is out of reach. Due to the level of talent the 49ers have on their defensive front seven, preventing Smith from achieving that goal will often take extra help.