In no particular order:
As of this minute, it seems like former sixth-round pick James Starks will be the odd man out when the Packers cut their roster to 53 players. Like DeShawn Wynn, a seventh-rounder in 2007, Stars has plenty of talent but simply hasn't stayed healthy enough to justify keeping him around any longer. Eddie Lacy and Jonathan Franklin are the kind of power backs for whom DuJuan Harris should be a nice change of pace. If one of the three gets injured (likely, given Lacy's long history of same) or McCarthy simply wants to be prepared for that happening, the Packers could keep Alex Green on the roster and carry four. Green has been the forgotten man this offseason; he's a former third-round pick in just his third season, and this year will be two years removed from his ACL tear. Green has a chance to surprise.
The knocks on Lacy are his injury history and his mediocre speed. Watching highlight videos of Lacy's Alabama career, he just doesn't look like a fast back. I think he will struggle some at the NFL level, what with defenders taking better angles on him and with a meh offensive line in front of him. At the same time, he reminds me a lot of Brandon Jacobs as a guy who just rams into people and will not go down easily. You know how a "possession receiver" is a guy who doesn't get open for 20-yard catches, but is really good at getting open for 5 or 8-yard gains and moving the chains? Lacy's going to be like that for the Packers. He's going to be really good at getting a solid 4-5 yards per carry and converting third-and-short opportunities. Just don't expect him to bust it for 60 once a game.
I think it's very possible that the Packers could open the season with Lacy, Franklin, Harris, Green and John Kuhn at running back. There should be a little extra space on offense, since they're unlikely to keep six wide receivers again. Greg Jennings and Donald Driver are gone, and while the top three are set in Randall Cobb, Jordy Nelson and James Jones, the bottom three--Jarrett Boykin, Charles Johnson and Kevin Dorsey--will likely be fighting for two spots.
I loved the Datone Jones pick. Everything I've heard about him is that he's a high-character, high-motor player and a good inside rusher. He's also tall and athletic, a big plus, and should fit right in as a starting 3-4 end and a nickel rusher next to B.J. Raji. Remember when Cullen Jenkins was providing fairly consistent inside pressure with Raji in 2010, something the Packers haven't had since? If quarterbacks are feeling the heat from Jones coming up the middle, that will instantly make life easier for Clay Matthews and Nick Perry coming around the edges. (Speaking of Perry, I'm really excited to see what he's capable of in Year 2. The Packers arguably haven't successfully turned a college DE into a starting 3-4 OLB yet--Matthews had 3-4 experience at USC--but Perry has more talent than any of the guys they've tried with.)
Mike McCarthy said that rehabbing tackle Derek Sherrod is still very much a part of the Packers' plans. The ideal scenario would be to have a rejuvenated Sherrod at left tackle and keep Bryan Bulaga at right, with Marshall Newhouse, Don Barclay and now David Bakhtiari backing them up. If Sherrod isn't healthy, they could try Bulaga at LT and have Barclay and Bakhtiari compete at RT. Either way, the Packers now have more options at tackle than they've had in some time. J.C. Tretter is the early candidate for the No. 1 backup at LG, RG and C, and might even compete with Evan Dietrich-Smith for the starting center spot.