Third-round draft pick David Johnson (right) meets fellow running back Andre Ellington for the first time last week. Ellington had already said he'd embrace whatever running back the team would draft.

Running back David Johnson sat in the cafeteria at the Cardinals' training facility last Thursday, eating lunch and talking casually with the other rookies.

On the other side of the westernmost wall, construction workers milled about, vacuuming, measuring distances and hanging signs inside the locker room as renovations within the building continued.

The Cardinals' third-round pick got his first taste of the NFL with rookie minicamp this weekend -- the culmination of a dream 15 years in the making -- but if he ever needs a reminder of where he came from, it takes only a peek through that locker room door.

Over the past five years, Johnson's star steadily rose at Northern Iowa, from redshirt to backup to record-breaking running back. But no matter how well he performed in a given season, every summer remained the same. Johnson

woke up at 5:30 a.m. each weekday for a maintenance job which lasted until 2:30 p.m., and followed that with several hours of football training. It was a rarity for Johnson to see six hours of sleep a night.

"In the summer a lot of people are on vacation," Johnson said, "but I had to do a job and work out. It definitely taught me not everything's given. You've got to work for everything."

After being lightly recruited out of Clinton (Iowa) High, Johnson enrolled at Northern Iowa in 2010. He was so athletic the coaching staff tried him in a number of different positions when he arrived, and Johnson eventually found his groove at running back. In his career, Johnson amassed 4,682 rushing yards, 1,737 receiving yards and 63 touchdowns. While the success may have made him popular on campus, there weren't many perks.

Johnson still needed money for housing over the summers, which meant working the various manual labor jobs alongside many of his teammates, including nose tackle Xavier Williams.

"I don't want to take away anything from anybody coming from a bigger program, but coming from a small program, the simple fact is you don't get as much, and it makes you respect the stuff you do get," said Williams, an undrafted free agent signee by the Cardinals last week. "We didn't get a lot of gear. Over the summer we're working in the hot-ass dorms, sweating all day, and then going to work out in the afternoon. It gives you a greater appreciation because that's what you could be doing all the time. It makes you think, 'I get to play a game that I love. I could be just doing crappy jobs.'"

For Johnson, the first summer was the worst. He needed a job, and accepted an opportunity removing asbestos. He

downplayed the harmful effect – "We didn't do the very potent stuff," Johnson said -- but it was still grueling work.

"There was a glue they used for tiles at schools and we'd go have to (remove) that," Johnson said. "We'd have to wear a suit with a mask, and it was about 100 degrees out. We had to go over there and scrape tiles off. It was like black tar we had to remove because it was harmful for the students. … It was definitely not a fun job."

The past three summers were still long but the situation was better, as Johnson worked under the guidance of Phil Chien fixing various issues inside the dorms. Johnson "was unfamiliar with a lot of maintenance things, but he was not afraid to learn," Chien said. "He said, 'Sure, show me what to do.' David's pretty handy. You can show him once and he can do it."

Johnson fit in with the rest of the group, although Chien would periodically get reminders Johnson wasn't his typical employee.

"There was one thing we had to tell him," Chien said. "When we tell you to snug (a bolt), we mean snug it for a normal person. He's a strong boy. He would tighten some stuff that no one else could open."

Johnson appreciates the work ethic borne out of those long days, but is ready to trade the tools for the pads full-time.

"I don't have to worry about getting up and cleaning toilets, cleaning drains and stuff," Johnson said with a wide smile. "I get to actually do what I love and get paid for it."

The Cardinals are counting on Johnson to aid a running game which finished last in the NFL in rushing yards per attempt in 2014. With an improved offensive line and a healthy Andre Ellington, he won't be expected to do it alone, but there is an opportunity to find a role immediately.

While some of his skills are similar to Ellington's, Johnson is about 25 pounds heavier, which gives the team the potential short-yardage back they lacked following Jonathan Dwyer's arrest after Week 2 last season.

In football parlance, picking up two yards on third-and-1 is doing the dirty work. Johnson knows the true meaning of that phrase, and he's hoping a long career will keep him far away from the asbestos summers.

"My boss, I talked to him," Johnson said. "He's done it for about 40 years. He just said, 'Man, you don't want to be here. If anything, get your education. And play football for as long as you can.'"