With Oklahoma's RB Adrian Peterson likely drafted in the top 3, California's RB Marshawn Lynch possibly drafted before the Packers pick at 16th overall, and GM Ted Thompson unlikely to trade up into the 1st round under any circumstance, its time to look at some other running backs.
Louisville's RB Michael Bush. He's big (6'1", 243 lbs.) and pretty fast in the 40 yard dash for a guy his size (4.50) according to NFL Draft Countdown. He averaged 5.8 yards/carry during his college career and scored 39 TDs in 36 career games. The bad news is that he's coming off a broken fibula suffered during the first game of the season. Although runners are usually slowed in their first season back from a ligament tear, with a broken leg the player is usually back to 100% by the next season, just ask WR Steve Smith who was the best WR in the NFL in 2005 after breaking his leg in 2004. Sometimes bad things happen, the bone is slow to heal, and there is a danger that necrosis can occur, such as in the case of RB Garrison Hearst. In Hearst's case, he broke the bone in January and by April the doctor knew there was a problem, so the Packers can find out now whether Bush is healed or if the recovery is too slow because Bush broke his fibula back in September 2006. If the bone is healthy now there should be no future concerns with it.
There might be rust because he basically missed the entire season, but the Packers already have RBs Vernand Morency and Noah Herron as an alternative if Bush needs time to get back into football shape. Since he is a big back he could either become part of a good rotation with Herron acting as the 3rd down back, or he could push Morency to improve on his mediocre 2006 season. The starting running back has to be a good receiver and Bush isn't that great, with only 50 career catches in 36 career games, and it isn't like Louisville didn't throw the ball much in their offense. However, he might have not been given the opportunity, so the Packers will have to evaluate his receiving skills closely. He is a possibility for the Packers in the 2nd round, pick 47 overall, but he doesn't appear to be a complete every down type back.