Cardinals right tackle D.J. Humphries blocks for quarterback Carson Palmer at a recent training camp practice.

For all the potential the Cardinals have on offense, it can get derailed by one weak link.

The unit is stocked with veterans, but it's the play of second-year right tackle D.J. Humphries that everyone will be watching closely throughout training camp. The former first-round draft pick was inactive for every game last season but is now the projected starter.

Quarterback Carson Palmer needs to trust Humphries can keep him upright, and he made a move to strengthen that bond by complimenting Humphries as they chatted after a recent practice.

"You don't just get confidence," Palmer said. "The more ways you can build that up besides just playing in games, the better.

"Mainly I was just saying, 'What's going to make you great is the way you compete,'" Palmer added. "He has (to have) a short memory. Bad things are going to happen. It's your first time playing on the right side of the ball and you've been on the left side the entire time. You don't have one rep underneath your belt going into the season as a projected starter. As long as you compete and play hard – you're going to make mistakes. We all do."

Humphries brought up the conversation unprompted with the media after Palmer's message, and it was clear it gave Humphries a mental boost.

"It really made me feel good," Humphries said. "It let me know that, even if the spotlight is on me, it doesn't matter because I'm doing what I'm supposed to do. I'm working hard. It's going to play out for me because I'm working hard and competing every day."

Palmer plans to be that reassuring voice moving forward.

"I've been there," he said. "You know how it is. Especially with D.J., just being in his ear and talking to him, that's going to be a big role of mine."

TO YELL OR NOT TO YELL

While Palmer and Humphries had a gentle, positive conversation, Bruce Arians is known to get his message across a bit more starkly. The coach-'em-hard-hug-'em-later disciple can be heard a couple times each practice blowing up on a player.

None dare to give it back to Arians, not even his quarterback.

"I haven't heard anybody yell back at him, and I'm not going to be the first," Palmer said.

Arians said Palmer gives his opinion, just not as demonstrably.

"I yell at him," Arians said. "He doesn't yell back. He voices his opinion very strongly. I wouldn't call it a yell."

ALANI FUA SUFFERS POTENTIALLY SERIOUS KNEE INJURY

Backup inside linebacker Alani Fua suffered a knee injury on Monday that could be serious, Arians said. He had an MRI on Tuesday and results should be known soon. Fua was a useful piece on special teams a season ago after making the team as an undrafted free agent.

Wide receiver J.J. Nelson injured his groin early in Monday's practice and sat Tuesday, but could be back by the end of the week. Defensive tackle Ed Stinson (calf) and wide receiver Franky Okafor (ankle) joined tight end Jermaine Gresham (hamstring), wide receiver John Brown (head), guard Evan Mathis (leg), cornerback Mike Jenkins (hand) and cornerback Elie Bouka (hamstring) as players who also missed practice due to injury. Palmer had a veteran's day off. Wide receiver Larry Fitzgerald was supposed to as well, but practiced because the team was short on available wideouts.

Arians said Gresham, Brown, Okafor, Mathis and Nelson could practice Thursday following the team's Wednesday day off.