There are no guarantees a player will improve upon his performance as a rookie. Sheldon Richardson seems like he's in a pretty good spot even if he doesn't get better as a second year player. If his rookie year is his floor, he is likely looking at a long and successful career as a big run stuffer. As a rookie he surpassed the expectations most people had of him. He was kind of like Mike Devito, and Devito is a very good and valuable player.
One of the big questions of year two will be whether he can become more. He was excellent against the run, but he was not a big impact player as a pass rusher. His technique looked quite raw. He didn't flash a ton of moves successfully to get to the quarterback, and he finished with only 3.5 sacks. Maybe I shouldn't say "only" 3.5 sacks because while he was not a great pass rusher, he developed way faster technically than anybody could have reasonably expected against the run, but you get the point.
The extent to which Sheldon can do more getting after the quarterback will have major implications for the Jets. If he remains purely a run stopper, you have a really good foundation on the defensive line. If he ever makes good on his potential, we're having a different discussion. Suddenly the Jets defense is built around two gifted all around 300 pound linemen in Sheldon and Muhammad Wilkerson who are difficult to block in any setting and are going to cause your offensive line headaches. You probably have All Pro talent in two places, and you have to choose between leaving at least one of these beasts one on one or exposing yourself to some very unfavorable blocking matchups on the outside.
How can Richardson get there? His pass rushing technique needs some work. He is going to have to develop some moves and learn how to use the strength in his hands and arms to his advantage. He has Karl Dunbar to teach him, but he also has his buddy Mo, who was in a similar position at one point in his career and can help him refine his craft.
Wilkerson can impart wisdom using two techniques in particular.
One is the rip move. Here's a basic video aiming to teach the youth of America this move.
Another is the swim move. Here is another basic video aiming to teach the youth of America this move.
Mo has these techniques in his arsenal and has found success using them. Of his 10.5 sacks last year, I counted 7 that ended as a result of one of these two moves. He used them to go both inside and outside linemen. What you have now in Wilkerson is a guy who can go high or low, inside or outside. That is why he has become such a productive pass rusher.
I think working on these techniques with Mo and Dunbar can help Sheldon. I also see great possibilities with Sheldon learning how to effectively use just a straight bullrush. He has such a great burst that he can gain leverage and knock linemen off balance with his strength. As he gains more experience and gains a better sense of timing snap counts, I think this is another weapon that could go into his arsenal.
Sheldon Richardson's nickname is the Boss Hogg. The question in front of us is whether he will be just a run clogging hog, or whether he develops the array of moves that can turn him into the same kind of monster against the pass that he already is against the run. There's no bad outcome for the Jets here. Worst case you still have one of the best young defensive lines in football. Richardson joining Wilkerson as an All Pro type player by improving his sack artistry puts a really high ceiling on what this defense can become in the forseeable future, though.