At first I was thinking about the expected 53-man roster. But Mike McCarthy has said that he doesn't "concern myself" with roster spots in May. "Create the competition and your roster will come to you." So instead of looking at the players who should make the roster, this is a look at the competition for each position. I'll start with the center position.
The big surprise in last April's draft was that the Packers didn't draft a center for the future. The only player they did add was undrafted rookie Tommie Draheim. He had a good college career at San Diego State, and he's the tallest center on the roster with almost ideal height for the position. But he's making the transition from college tackle, and expecting anything from him next season is speculative.
The Press-Gazette ran a nice story on Sampson Genus, who admitted that he wasn't ready to play last season, though he should benefit a lot from the offseason programs. His listed height of 6-1 is very generous but whether it's truly a detriment is yet to be seen. I think the coaches have to like his potential otherwise they would have brought in someone more likely to contribute in 2012 than Draheim.
Evan Dietrich-Smith was a surprise to make the roster in 2009 as an undrafted free agent, he was released in 2010 after a poor preseason, and he was a surprise returning player in 2011. That said, the Packers have little experienced backups to compete with him, and no other player has been given the opportunity to play multiple interior line positions. With the signing of Saturday, he appears to have no shot to become a starter, but they probably want to keep him around for depth. And he'll always have his highlight with Ndamukong Suh.
Overall competition level: weak. Saturday's the starter, Dietrich-Smith is probably not in a real competition since he'll back up three positions, and Genus should have the inside track for a return trip to the practice squad, if he isn't one of the last players to make the 53-man roster. Unless the offseason program really transforms Draheim into a legitimate option, he should be one of the early cuts this preseason.