"I tried to, but it seems it's on my shoulder" Mathieu said through a smile Sunday. "I don't know. I just go with the flow."
Mathieu has, however, been able to shake his off-the-field issues, at least so far, as he tries to build a new reputation at the start of his professional career.
"I think everything's going good," Mathieu said Sunday. "It's been extremely positive for me. A ton of guys in the locker room, they all support me and they know my situation. They all hold me accountable, and I think that's something I needed coming into the NFL."
Chief among those teammates is Mathieu's close friend and former LSU teammate Patrick Peterson. Peterson has been a mentor to Mathieu for some time, helping him transition to NFL life while also doing what he can to keep Mathieu on the straight and narrow.
Mathieu has remained largely out of the spotlight since being drafted by the Cardinals in the third round in April and has impressed team officials so far. General manager Steve Keim on Sunday called Mathieu's offseason "outstanding."
"The thing that I didn't know for sure when we drafted him is what his commitment to the game is like in terms of preparation," Keim said. "He's a gym rat. He was one of the rookies that was first in the weight room every morning."
Mathieu's career at LSU ended after he reportedly failed multiple drug tests, leading coach Les Miles to dismiss him. Mathieu also was arrested last October for possession of marijuana. He did not play football in 2012, which naturally hurt his draft stock.
The Cardinals decided Mathieu was talented enough to take a risk at No. 69 overall, and Mathieu eased concerns about his track record by voluntarily entering the NFL's drug-testing program.
With the offseason quiet and free of controversy, Mathieu has been able to focus almost exclusively on football.
"I had some fun, had to get away from football and just get away, but it was pretty much all football for me," Mathieu said. "I was at the facility most of the offseason just working out, trying to get in shape."
Mathieu recognized he had some catching up to do after a season away and has taken extra motivation from those who doubted him as an NFL prospect and a person.
"He's obviously got a chip on his shoulder," Keim said. "Now we'll see whether he toes the line off the field, but so far, everything we've seen gives me a great deal of confidence that he's going to the do right things."
Mathieu says he has gotten past any nerves that came with his first NFL training camp and is getting comfortable on the field, though he admits he's still got plenty to learn. One thing that hasn't changed: the attention he gets from fans.
Mathieu may be the team's highest-profile draft pick ever, and he already has a host of loyal fans shouting his name -- be it his real name or "Honey Badger" -- from the stands at University of Phoenix Stadium. The attention doesn't appear to be going to his head.
"I have a lot of fans, and of course I'm happy those guys still root for me and still cheer for me," Mathieu said. "But I think my biggest thing right now is I need to make a few more big plays so hopefully I'll get a few new fans."
TIGHT END ADDED
The Cardinals on Sunday announced the addition of tight end Mickey Shuler via a waiver claim from the Buffalo Bills.
Shuler, 6-foot-4 and 247 pounds, was a seventh-round pick (214th overall) of the Minnesota Vikings in the 2010 draft out of Penn State. He played parts of his rookie season with the Vikings and Dolphins. He was claimed off waivers by the Bengals before the 2011 season but failed a physical and ended up returning to Minnesota during the season. He spent 2012 on the Raiders practice squad and was claimed off waivers by the Bills in May but released Saturday.
Shuler, 26, has two career receptions for 44 yards.
"Mickey's a talented guy," Keim said. "We've had some concerns with our depth at that position and thought it would be the right thing to do to claim him once he hit waivers.
"He does have some length to him, he's a pretty good athlete. ... For a guy that's on the streets at this time of year, I think it was a good decision."
Wide receiver Robert Gill didn't make it through the Cardinals' second practice of training camp, leaving with an athletic trainer about halfway through the 2 1/2-hour session.
Cardinals coach Bruce Arians said Gill re-strained the hamstring injury that delayed his offseason audition with the team. The speedy 29-year-old rookie, Arians said, will "hopefully" miss only 7-10 days.
Gill stood out on the first day of camp, catching a deep touchdown pass. He's battling four or five others for the final two or three wide receiver jobs.
-- With the additions of Shuler and offensive guard Jonathan Cooper, who agreed to terms on his rookie deal Sunday, the Cardinals' roster is full at 90 players.
-- Running back Ryan Williams sat out Sunday's practice with a wrap on his right knee. Right guard Daryn Colledge also sat out with an apparent right leg injury.