Here's something that's more difficult to answer: Why?
Are the Packers legitimately interested in Hillis, whose production has declined steadily since his 1,177-yard season for the Cleveland Browns in 2010? Or are they using Hillis as leverage against free-agent Steven Jackson, who could be asking for more money than the Packers are willing to pay?
Generally speaking, the Packers don't strike me as the type of organization to play those kinds of games. They haven't often hosted veteran players on visits during general manager Ted Thompson's tenure, and when they have, it has usually been as the result of genuine interest.
The Packers could certainly use help at running back, but I'm not sure what Hillis would add to the Packers' offense unless they consider him an upgrade over John Kuhn. I'm not sure how many people envision Hillis as a full-time starter on a playoff team. We'll see where this goes.