The question is whether the addition of rookie RBs Eddie Lacy and Johnathan Franklin make the Packers' running game better? The answer is "duh" but Rivers McCown at ESPN.com (Insider required) actually goes through the stats and explains why it will improve.
First, he points out that the Packers' running game wasn't all that bad last season (FO ranked them at No. 13 overall). It's not that RB Alex Green was all that good (he wasn't) but QB Aaron Rodgers is a good rushing quarterback and no defense was lining up eight players in the box to stop the run.
The big problem he notes is that their running backs were lousy at breaking tackles. This has been obvious for a while; the Packers haven't had one capable of making a move in the open field since RB Ryan Grant in 2007.
And both Lacy and Franklin are very good at breaking tackles. Rivers McCown pointed out this breakdown from The Sideline View that ranked Frankin and Lacy as the second and third best backs in college last year for yards after contact. The best back was Giovani Bernard, who was a surprise as the first running back taken in the draft, but maybe it's not such a surprise considering how good he was at fighting for extra yards.
So while the Packers haven't had a back capable of making a defender miss in the open field or powering forward for tough yards in recent years, they now might have two of them.