Safety Tyrann Mathieu takes part in his first practice Wednesday after tearing his ACL and LCL in a December game.

Tyrann Mathieu's first day at practice since shredding his knee in a game a little more than eight months ago was a short one.

The safety went through individual drills as expected, and then left practice to do work away from the field. He returned late in the practice, pads off, to watch his teammates like he had done for all of camp.

"Felt like a toddler taking my first steps today," Mathieu tweeted afterward.

But earlier in the day, Mathieu wore a big smile, knowing he was getting back to practice and

making another move toward returning in time for the Cardinals' Sept. 8 regular-season opener. That Mathieu will play in that game is far from certain, but he is hopeful.

"I am just waiting for that moment when I really get tested and I will know for sure if I am the same player," Mathieu said.

Matheiu and defensive tackle Alameda Ta'amu, both removed from the physically-unable-to-perform list Tuesday, were both limited to brief drills. Coach Bruce Arians said that would be the course of action "for a day or two" and the Cardinals will judge each daily to when they are able to up their workload.

Both Mathieu and Ta'amu, who tore his ACL three weeks after Mathieu did, have been aiming for the season opener.

"It's up to them, and we'll see how the progress is," Arians said. "They've amazed me to get to this point. I'd be amazed if they were playing on Monday night."

"It felt like I'm back in football mode," Ta'amu said.

Mathieu is back sooner than the Cardinals had counted on him being back. He will wear a brace on his left knee (much to his chagrin) although he said he has already grown comfortable with the new piece of equipment.  

He insisted he won't rush the process. The Cardinals won't rush him either, although a Mathieu at full strength makes a big difference to the defense.

"He brings a different game-changing player," Arians said. "He's a game-changer. That's what you look for in practice, is he getting his hands on balls, tipping balls, intercepting balls? And (you watch) the speed with what he's playing."

Mathieu said he has sought advice. Wide receiver Michael Floyd, who had been working with Mathieu outside of practice when Floyd was sidelined with his bad groin, told Mathieu he looked good running last week.

Mathieu also talked to linebacker Desmond Bishop, who also suffered an ACL injury last season and told Mathieu once he got past the initial rust "it was all downhill from there."

"The other part is not feeling sorry for myself," Mathieu said. "There will be days when I am sore, in the middle of a game where I'll be sore I'll get tight, but I have to push through it. I think it's all about what I tell myself. I want to keep positive thoughts in my mind and not drown it with negativity."

PRACTICE-SQUAD CHANGES WON'T IMPACT QBS

Arians, not surprisingly, said he loves the new practice squad rules that not only allow teams to keep 10 instead of eight players but that two of them are allowed to have already played two accrued seasons – meaning that basically every player who came into the league since 2012 can

be on the practice squad, regardless of how much they have already played in regular games.

"I was shocked to see who was eligible," Arians said, breaking into a big smile. "I told Mike Floyd, 'You're lucky, you're practice squad eligible now. You might want to get out of the training room.' Jokingly, obviously.

"It changes a lot when you start looking through that waiver wire, who is going to be eligible, who is on your ballclub now eligible. I think it's a great rule."

That doesn't really change Arians' thoughts on keeping an extra qiuarterback though, even though Ryan Lindley is now eligible for a practice squad. "There's really no room for four (QBs)," Arians said, citing the inability to get even the third QB enough practice reps. "I might allow teams to do to two (QBs) and put a third on the practice squad."

Anyone going to the practice squad must still clear waivers after being cut, and is subject to being claimed by another team.

SENDLEIN HAPPY TO BE BACK

Starting center Lyle Sendlein returned to practice Wednesday from a calf injury he suffered early in camp, and it's been a long three weeks waiting to return.

"It hurts," Sendlein said. "I had never missed  camp practice in eight years. I pride myself on being a lunch-pail guy and being out there every day. It was a mental battle as well as a physical battle."

Arians limited Sendlein's snaps but the veteran is expected to play Sunday and be ready for the regular-season opener.

STARKS, MINTER, COOPER REMAIN OUT

Wide receiver Michael Floyd was among the players returning to practice Wednesday. The only three players still hurt and not practicing were guard Jonathan Cooper (turf toe), linebacker Kevin Minter (pectoral) and tackle Max Starks (ankle).