GLENDALE, Ariz. -- Sunday after Sunday, D.J. Humphries watched his Arizona Cardinals teammates suit up without him.

He was the only healthy first-round draft pick in the NFL to sit out every game last season as inactive.

"He was too immature," coach Bruce Arians said.

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Humphries wouldn't argue otherwise.

"To be honest, this type of team, what they demand for a player," he said, "I wasn't ready to give that to the team last year."

He'd better be ready now. Humphries is penciled in as the starting right tackle on a team that expects to contend for the Super Bowl.

To say he's looking forward to finally getting his chance is an understatement as big as he is.

"I'm almost jitterish, I'm so anxious," he said.

Early on last year, Humphries earned the nickname "Knee Deep" from Arians because that's how far his foot had to be up Humphries' rear end to get his attention.

But slowly, steadily, he improved.

"The biggest thing was get stronger and learn that it wasn't going to be easy," Arians said Saturday before practice at training camp. "It had been easy his whole life. He was just plugged in as a starter wherever he's been, and it wasn't going to be that easy. He had to learn to work every single day, prepare every single day to become a pro. He was more than ready by Thanksgiving."

Still, Humphries only watched as Bobby Massie held down the right tackle spot. But Massie was in the last year of his contract and the Cardinals weren't willing to spend the money it would take to re-sign him. The job would go to Humphries. So far, the team hasn't added a veteran tackle to push the 22-year-old or take over if things fall apart.

"People already explained the example to me," Humphries said. "They go out and get an older guy, that means you're not doing something right, or you're not living up to what they thought you would be. To see that not happen, clearly I'm doing something right. Clearly they know I'm taking it seriously. Clearly they see me make the effort and strides to do what I've got to do."

After a year of conditioning and working in the weight room, the big guy with a big personality said he's noticeably stronger.

"Nineteen percent body fat, 310 (pounds)," he said, smiling. "I look good."

The Cardinals made Humphries the 24th pick overall in the draft but, after only two seasons at Florida, strength, as well as maturity, was a problem.

"A lot of stuff I don't have problems with because I'm athletic," he said, "but the thing I have a problem with is because I'm not as strong. So I knew athleticism was not something I would have to worry about. Getting stronger and getting bigger and getting more stout, that was something that was going to help me in the confidence lane, how I feel about myself, and physically on the field."

Arizona signed 11-year NFL veteran Evan Mathis in the offseason to play right guard, and his experience should help the youngster who lines up next to him.

"Every little thing I think about, he's right there," Humphries said. "Between him and (center) A.Q. (Shipley), it's automatic. I don't have to think too much about it."

Actually, there's a lot to think about.

The protection schemes are far more sophisticated than what Humphries dealt with in college.

"We have 18 to 20 different protections," Arians said. "They might have three. They don't see the number of fronts and blitzes that they have to handle here."

So the pressure is on. Protecting Carson Palmer is the No. 1 priority of the offensive line, which will have a new center, a new right guard and a new, very young right tackle.

"My dad's been telling me since I was little," Humphries said. "Pressure breaks pipes, pressure makes diamonds. Either you're going to bust or you're going to be a diamond at the end of it. After I let my pipe bust last year, I've a chance to make this into a diamond."

NOTES: Arians said first-round pick Robert Nkemdiche will be sidelined about two weeks with a high ankle sprain. Cornerback Mike Jenkins broke a bone in his hand in Friday's opening camp practice. ... Arizona signed rookie wide receiver Frank Okafor and released wide receiver Rico Richardson.