Cardinals money linebacker Deone Bucannon earlier this offseason.

Deone Bucannon recently underwent ankle surgery, putting into question his availability for the start of the regular season.

The Cardinals' money linebacker went on injured reserve in mid-December because of the bothersome ankle, and the issue lingered this offseason. Coach Bruce Arians said the Cardinals hope to get Bucannon back in September. The team opens the season in Detroit on Sept. 10.

"We think, if everything goes perfect, he'll be ready," Arians said. "But there's always that chance that it won't."

Bucannon missed the final three games of 2016 after dealing with the ankle issue much of the year, but thought he could rehabilitate it without surgery. Bucannon is known as one of the hardest workers on the team, and his teammates believe he will get back on the field quickly.

"Knowing how Buc is, he's going to put the work in to get back," outside linebacker Markus Golden said. "He ain't going to miss a step. He's going to be in the gym still working out. He's going to be in shape. For him, I'm glad he's able to get his ankle ready. He'll be more prepared whenever the season comes. He won't be feeling soreness in his ankle."

[READ: WITH BUCANNON DOWN, REDDICK IS UP]

First-round draft pick Haason Reddick has been elevated to Bucannon's starting spot for offseason work next to inside linebacker Karlos Dansby. If Bucannon can't play early in the season, Reddick would be quickly thrust into a major role.

"It's not intimidating," Reddick said. "I've got to step up now. I've got to be ready to go out there, make plays and be somebody that the team can count on."

Reddick played defensive end in college and is hoping to make a smooth transition.

"He knows how to rush the passer," Arians said. "We don't have to teach him how to rush the passer. He's learning all about sight lines and reads and all those things it takes to play off the ball."

RENEWED CONFIDENCE FOR JOHN BROWN

The John Brown who gave defensive backs fits in his first two seasons was back during OTAs on Tuesday. After a frustrating 2016 in which he dealt with health issues, Brown was zipping around the field and hauling in passes.

"A couple of those routes he ran, he did not run one route like that last year," Arians said. "He couldn't. And the smile on his face and him laughing – just knock on wood it stays that way."

After several months in which Brown didn’t even have the energy to play with his daughter, he feels back to normal, which has him excited about the upcoming season.

"My confidence is through the roof," Brown said. "I'm just ready to go out there, prove to everybody I'm back and help my team in any way I can."

ARIANS HAPPY WITH OTA START

The beginning of organized team activities was accompanied by cloud cover, which naturally improves the mood, but Arians said a jovial nature has been present throughout the offseason.

"We had a business-like attitude last year, but this one is a more relaxed, more fun group of guys," Arians said. "They really enjoy doing what they're doing."

This was the first day the rookies joined the veterans on the field, and Arians said it went smoothly.

"Outstanding start," Arians said. "Extremely pleased with how the young guys jumped in there. We were probably 25 minutes ahead of time, which is always a good sign if it's quality work."

One thing that drew his ire: multiple wide receivers missed either some or all of practice with hamstring issues "because they don't know how to get in shape," Arians said.

TERRY ALLEN CHOSEN FOR BILL BIDWILL COACHING FELLOWSHIP

Former Pro Bowl running back Terry Allen has been named the new Bill Bidwill coaching fellow. The program, named after the Cardinals' owner, provides recently-retired NFL players with a way to get experience coaching in the NFL.

Allen will spend two seasons mentoring the Cardinals running backs. He follows former Steelers linebacker Levon Kirkland, who was the inaugural recipient of the fellowship from 2015-2016.  Arians said the team had an extensive search to find the next fellow and Allen stood out.

"He was a great player, but he's also got the fire to get back into football," Arians said. "We're really happy to have him on our staff."