EDEN PRAIRIE, Minn. — Tommy Armstrong is used to surveying the field before the snap.

As the former starting quarterback for the University of Nebraska, Armstrong would line up near the line of scrimmage and try to get a read on what the defense was going to do.

Armstrong surveyed the field Thursday morning at Winter Park, but he was as far away from the ball as possible.

The 23-year-old was signed earlier this week as a safety and is transitioning to play defense instead of offense.

"It's pretty much the same, honestly," said Armstrong, who joined the team on Tuesday. "You look for keys, look for things that tell you what's going to happen.

"Quarterback is the same way … you look for tendencies and safeties and identify different coverages," Armstrong added. "You have to know exactly what you have to do (on both sides of the ball)."

Armstrong was a three-year starter at Nebraska and became the first player in school history to pass for more than 2,000 yards in three consecutive seasons.

He set multiple Cornhuskers records, including starts by a quarterback (44), total offense (10,690 yards), total touchdowns (91), pass completions (625), touchdown passes (67) and passing yards (8,871).

"I wanted to help a team regardless of what position it was," Armstrong said. "Having this opportunity with the Vikings has just been a blessing.

"Most people would just give up after playing one position and sticking to that position throughout the process," Armstrong added. "Just having my inventory open and having an open mind to help a team really helped me a lot."

Vikings defensive backs coach Jerry Gray said Thursday that Armstrong obviously has some work to do in learning the techniques and finer points of being a defensive back.

But Gray noted that Armstrong's intellects have stood out early.

"He's really bright and understands what's going on around him," Gray said. "The good thing is that he doesn't have to be on the field to ask good questions. We'll be in a meeting and he'll ask, 'Coach, what does this or that mean?'

"I'll be talking to other guys and he takes notes on them," Gray said. "That lets me know he's aware of what's going on around him. When he gets out there, he picks up things really fast."

Armstrong said he's immersed himself in the playbook and has leaned on fellow rookie safety Jack Tocho. The duo lined up together on the third-team defense on Thursday.

Armstrong said a relentless approach to studying film has also helped.

"I'm learning a lot faster than I thought I would," Armstrong said. "I'm studying as much film as I can in my off time. I came in four installs behind but I've talked to Jack and we sit down at night going over all of the installs.

"Most of the time, it's a long day and a long process. You want to go home and go to sleep but I go home and stay in the playbook," he added. "I try to get a jump start on the next day. The key is just coming out here and being prepared."

Gray noted that Armstrong's time as a quarterback could help ease the transition to safety.

"I think it's a plus because he had to learn what everyone else was doing," Gray said. "Just take that same concept and put him at safety. Most people move quarterbacks to defensive backs in college, he just happened to do it one step later.

"As he takes what he learned at quarterback and applies it to safety, I think he's going to grow a whole lot faster," Gray said. 

Armstrong isn't the only former quarterback in the secondary, as cornerback Tre Roberson was a signal caller at both Indiana and Illinois State. Vikings running back Jerick McKinnon and rookie tight end Bucky Hodges also initially went to college as quarterbacks.

When Armstrong went out for his first day of practice during Organized Team Activities, his No. 31 jersey was without a nameplate.

That changed Thursday, as Armstrong continued on his journey to make it to the NFL.

"They were just getting my jersey ready," Armstrong said with a laugh. "Just having a jersey — with or without my last name — has been a blessing and I'm ready to take advantage of it."