Football is here – officially – as the Green Bay Packers report to training camp today and start the 2013 championship season of the National Football League.

The Packers are coming off an 11-win season, but there are plenty of questions surrounding the defending NFC North champions as they open up camp and eventually move into preseason games the first full week of August.

Here are five important ones the Packers hope to have some kind of feel for by the start of the regular season on Sept. 8 in San Francisco:

1. How quickly will the offensive line flip mesh together?

Packers head coach Mike McCarthy raised eyebrows by deciding that the best way to fix an offensive line that allowed 51 sacks of Aaron Rodgers was to not bring in new personnel, but to move Pro Bowl right guard Josh Sitton and starting right tackle Bryan Bulaga to the left side. Left guard T.J. Lang was moved to the right side, as was last season’s left tackle, Marshall Newhouse.

Quarterback protection has been an issue since Rodgers took over under center in 2008 – Packers’ quarterbacks have been sacked 215 times and Rodgers’ 202 times – and how well, and quickly, all four of those players adjust to moving their bodies in a different direction may determine the fate of the season.

2. What kind of player is Nick Perry?

The Packers’ 2012 first round draft pick played in six games last year before his season was ended with a wrist injury. In those six games, he recorded 18 total tackles and two sacks, but the injury occurred in Week 1 and perhaps affected his performance in the games leading up to his eventual trip to injured reserve.

Perry seems to be healthy now, and it is his second year in Dom Capers’ 3-4 scheme, but it’s basically his rookie season on the field. True, camp is camp and the preseason is the preseason – but these practices and games matter for a young player who missed so much time.

3. Can Jeremy Ross be the primary kick returner?

During offseason training activities, McCarthy said how many times Randall Cobb drops back to return kickoffs or punts will be determined by his teammates. Ross played in five games, returning four punts for 103 yards with a long of 58 yards and three kicks for 86 with a long of 44. Of course many remember his muffed punt against the 49ers in the Packers’ playoff loss, but the Packers coaching staff likes the third year pro out of California.

4. Will Mason Crosby return to form?

After a rough 2012 in which Crosby went 21 for 33 (63.6 percent) on field goal attempts – by far the worst performance of his six year career – the Packers brought in rookie Giorgio Tavecchio to push the veteran. Crosby was coming off a stellar 2011 when he led the NFL in extra points made (68) and attempted (69) and converted 85.7 percent of his field goal attempts.

5. Which running back will emerge?

General manager Ted Thompson surprised some by drafting Alabama running back Eddie Lacy No. 61 and UCLA running back Johnathan Franklin at No. 125. They enter camp alongside last year’s late season revelation DuJuan Harris, last year’s leading rusher Alex Green and 2011 leading rusher James Starks.

It’s an interesting mix of players, and while the Packers have had three different leading rushers the last three seasons, one would think McCarthy and offensive coordinator Tom Clements would like one of these guys to establish himself a la Ryan Grant when he rushed for more than 1,200 yards in back-to-back seasons in 2008 and 2009.