You just never know.
Two years ago, the Packers were coming off a playoff appearance and were touted as Super Bowl contenders, yet, three undrafted rookies managed to crack the 53-man roster out of training camp.
Then last year, as defending league champions with an even more seasoned roster, the Packers still had two undrafted rookies who stuck around after final cuts.
Those five aforementioned players – Sam Shields, Nick McDonald and Frank Zombo in 2010; Jamari Lattimore and Vic So'oto in 2011 – beat the odds by showing up in the preseason games. Receiver Chastin West, a practice-squad holdover, did so last year, too, and even though he was released, his work earned him a job elsewhere when he was claimed off waivers.
Training camp practices always carry some weight, but performing in unscripted, live action against an actual opponent will never escape the eye of talent evaluators and decision-makers.
That all-important preseason begins Thursday night for the nearly three dozen rookies and first-year prospects the Packers will bring to Qualcomm Stadium in San Diego. Some, like high draft picks Nick Perry, Jerel Worthy and Casey Hayward, are locks to make the team. Most are looking to unlock a door to their dreams.
"Every year there are always surprises," General Manager Ted Thompson said. "It's a fascinating time of year for us in the personnel business, because you have this idea of how things will go based on something you've seen in the past. But then to actually watch these guys, especially the young guys, play the game, you're always surprised.
"Sometimes it's a good surprise, sometimes it's a not-so-good surprise."
The Chargers are resurfacing as a Packers preseason opponent. Mike McCarthy began his head coaching career with a trip to San Diego in early August 2006, and the Packers hadn't been back until last November, when Green Bay held off a Chargers rally from a 21-point fourth-quarter deficit for a 45-38 victory.
The Packers have opened their last three preseasons against the Cleveland Browns, and they are the opponent next week. Over those last three preseasons, the Packers are 8-4, with three of the four losses coming on the road.
The starters won't play long enough to roll up a score like last year's regular-season shootout, and both teams are looking to retool previously formidable defenses that slipped a year ago.
With that in mind, here are a handful of things to watch closely on Thursday night:
Graham Harrell – At this point, the Packers believe Aaron Rodgers' insurance policy can be a former spread-offense college quarterback who has never resided higher than third on the depth chart until now. The Packers also believe in their ability to develop quarterbacks, and the next stage of Harrell's development begins now.
The defense's new faces – Perry, Worthy, Hayward, safety Jerron McMillian and defensive lineman Mike Daniels all could play contributing roles on defense as rookies, and they've only got four games to get ready for the opener. Daniels is injured and may not play on Thursday, but Hayward and McMillian figure to get a lot of snaps in the secondary. As base and nickel starters, respectively, Perry and Worthy could get more work than the veteran starters, who might play only a series or two.
Big plays – The Packers defense's biggest downfall last year was getting gashed for huge chunks of yardage. San Diego's Philip Rivers and Co. can be as explosive as any offense, and even though the Chargers' first unit likely won't play much either, avoiding any big plays would be a positive start.
Herb Taylor – Starting left tackle Marshall Newhouse is out with a concussion, and 2011 first-round pick Derek Sherrod still hasn't practiced this summer, so Taylor gets the start protecting Rodgers' blind side. As far as the "second string" goes, the offensive line has attracted nearly as much attention as Harrell, and Taylor needs to prove he can be counted on for depth up front.
Special teams – The key to a roster spot for any young player who's not a starter is to contribute on special teams. So keep an eye on who's throwing the key blocks and making the tackles on punt and kickoff returns, even late in the game when it hardly seems to matter. The special teams depth chart is always in flux, and one play could change someone's fortunes.