Scott Tolzien, throwing a pass to receiver Jordy Nelson during OTAs Tuesday, is competing with Matt Flynn for the No. 2 quarterback job. Credit: Mark Hoffman

By of the

Green Bay — Most of November, his head was spinning. Sleep was a luxury.

The Green Bay Packers' season was on the brink of collapse and they asked Scott Tolzien to save it.

Sitting in his locker, the backup quarterback thinks back to those three weeks as the starter.

"It was definitely a cram session at times," Tolzien said Tuesday. "But that's my job. That's what I'm here to do. My job is to learn it and execute it."

Tolzien had his moments. He knifed six deep completions downfield at New York. He spun past future Packer Letroy Guion for a rushing touchdown against Minnesota.

He also was benched.

Now, Tolzien can take a deep breath and truly learn the offense. This year he's challenging Matt Flynn for the No. 2 job behind Aaron Rodgers, which — the Packers learned the hard way — may be the most important camp battle of them all. Flynn is the fan favorite, the one who rallied Green Bay to comeback wins over Atlanta and Dallas. His heroics led to a one-year deal in the off-season. For now, Flynn is taking the reps behind Rodgers.

Yet through organized team activities, Tolzien's superior physical ability — the stronger arm, the upside — is again on display. It's on him to catch Flynn mentally.

"We have three weeks left so I have to ways to go," Tolzien said. "You see made progress, but I have a ways to go."

Last November, Tolzien said he was learning the offense on a "101" level. Now he's up to "301."

Signed to the practice squad on the eve of the regular season, Tolzien was thrust into action Nov. 10 against Philadelphia. He burned the New York Giants for completions of 52, 45, 29, 26 and 25 yards. He also threw five interceptions in the losses to Philadelphia and New York before Flynn replaced him against Minnesota.

In all, Tolzien completed 61.1% of his passes for 717 yards with a 66.8 passer rating.

With months instead of hours to prepare, Tolzien is making more structural changes to his game. Coach Mike McCarthy noted that coaches have changed Tolzien's footwork. His three-, five- and seven-step drops have been under construction.

"Every offense has a timing aspect and a rhythm," Tolzien said. "Some of it is just getting your feet in tune with the routes....There are so many little intricacies to it that it's hard to explain. At the end of the day, you're really trying to have your feet in a balanced position and in a rhythm to throw with the timing."

Of course, McCarthy also spent multiple off-seasons doing the same thing with Graham Harrell and B.J. Coleman.

He's hoping for a different finished product in Tolzien. On Tuesday, he called Tolzien a "tireless worker."

Said McCarthy, "I don't know that there's anyone in the program who spends as much time (preparing) as Tolzien."

The competition is under way.

During Tuesday's open OTA, Flynn had a back-shoulder attempt to Kevin Dorsey intercepted by Davon House. Moments later, Tolzien gunned a completion to Chris Harper. Flynn said afterward there is "no guarantee" he has a spot on the team, even after re-signing.

For Tolzien, it'll boil down to a grasp of the playbook. After a monthlong break from football, he's been taking up residency off Lombardi Avenue. This is the same player who famously slept over at the San Francisco 49ers' facility.

Still, Tolzien cautions that he still has a long way to go in reading defenses.

"You're working on the fundamentals, the timing on your routes, your protections, your reads, learning defensive terminology, it's all-encompassing," he said. "My focus is every day trying to maximize. You only get a few opportunities in the summer."

Tolzien admits he couldn't execute the audibles at the line those three games last season as he could today. Green Bay's offense was watered down then. The result was three touchdowns in 10 quarters of play. With Flynn, the pre-snap adjustments picked up. This is where the former Wisconsin Badger must play catch-up.

"There's an added comfort now," said Tolzien, who no longer has practice-squad eligibility. "Being more in tune with checks. Ultimately, it's always on your plate to do that. But it's your job to execute it.

"I think it all starts in the meeting room. You have to know what you're doing there first before you get on the field. It's five times faster on the field. So your decisions have to be that much quicker. You have to have it down pat in the meeting room first. And then you take it out to the field."

The Packers didn't draft a quarterback, instead picking up project Chase Rettig afterward.

Behind Rodgers, it's Tolzien vs. Flynn. It's potential vs. what's proven. The Packers saw enough in Tolzien to give him a full off-season.

He realizes the stakes. And the Packers, after 2013, surely do too.

"I've been there in the past, in college and the pros, too," Tolzien said. "Really, the focus is on yourself — always improving yourself. You can't worry about the other guys, because that's your teammate, too. My focus is on myself and how I can improve myself each day."