Lacy has the patience to anticipate when run lanes in front of him will open up and will run quickly and powerfully through them. Where Lacy runs into trouble is that he'll miss cut back lanes about to open up in his peripheral vision. An couple of anecdotal examples of this are at about the 8:10 mark in the third quarter of the 2012 Arkansas game: Lacy dives headlong into a pile of bodies in front of him as tackle D.J. Fluker kicks out the defensive end to his right and creates a massive run lane; if Lacy had anticipated this gap he would have likely gone for a six yard gain instead of a two yard gain. Another example is the 7:15 mark of the third quarter of the 2012 Florida game: Lacy continues running right into traffic but to his left he had a free guard that would have been in position to block out the linebacker and had a whole lot of green grass. This isn't to say Lacy's vision is poor, he does find cutback lanes and anticipates gaps opening up, but he needs work. I'll present Doug Martin as an example of a player who started his rookie year with vision about on par with what Lacy has now, who managed to improve his ability drastically as the year went on. Hopefully Lacy can do the same.
The reason that Lacy's somewhat limited vision is less of a concern is his bruising running style. Even when Lacy dove into massive piles of humanity instead of taking cutback lanes, he was often about to move the pile to gain two or three yards where most backs would simply be stood up. When Lacy is moving through gaps, he's able to fit through extremely tight spaces when running, allowing him to sometimes hit gaps a little early or late and still move through it and into the second level. Lacy has decent acceleration when moving to hit a hole but doesn't seem to stride well, that is, the top speed that Lacy possesses isn't good enough to separate from defenders in the second level. Lacy has a decently sharp cut and a spin move that allows him to avoid defenders even in traffic around the line. Lacy also has a vicious stiff arm to keep tacklers at bay. Lacy does need to work on ball security a bit, as he can occasionally get lazy maintaining three points of contact with the ball. Still, no real big concerns with Lacy's running style.
Pass protections is certainly an area where Lacy needs work. Lacy tends to allow defenders to attack him instead of moving up to meet them. This tendency was a particular problem in shotgun formations where Lacy would often cut directly in front of his quarterback to meet blockers instead of moving up to meet them away from his quarterback. When Lacy engages the defender he tends to try to use his shoulder to block instead of extending out with his arms to kill the rush. While this was effective on at a college level, it's not going to work in the NFL. Lacy's saving grace as a pass protector is that he would usually identify the most threatening defender when more than one were moving into the backfield to give his quarterback as much time as possible.
Lacy is very adequate pass catcher, showing soft hands and the ability to catch away from his body. Lacy isn't particularly good in the open field; when he doesn't have a head of steam as he would as rusher, he doesn't show the agility to shake off defenders. Lacy also understands in situations where he is pass blocking when to move out to be an outlet for his quarterback which often salvages plays.
Overall, Lacy is a bruising back with a good cut and the patience and acceleration to time when he hits gaps. Lacy's major drawbacks at the moment are his pass protection and the inability to always find the cutback lanes that are presented to him. Fortunately, the problems Lacy has are correctable and I see Lacy as the Packers' workhorse back for years to come. He was most certainly a value at pick 61.
Check out all of Acme Packing Company's draft coverage: 2013 NFL Draft Central | Green Bay Selects Datone Jones in First Round | Green Bay Drafts Eddie Lacy in Second Round | Packers' Complete Draft Order