On Sept. 9, 2007, Joe Thomas, the third overall pick in the 2007 NFL Draft, took his spot at left tackle for the Cleveland Browns. At the time, Thomas didn’t know that he would play 11 seasons at the position, providing a constant presence for Cleveland before eventually becoming a Pro Football Hall of Fame Class of 2023 inductee. 

Instead, he was worried about one thing: Pittsburgh Steelers defensive lineman James Harrison. 

But an even more nervous feeling entered Thomas’ body recently when he visited Randolph Air Force Base in San Antonio on behalf of USAA, the official NFL Salute to Service partner, to experience a day in the life of a military working dog unit. 

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

Joe Thomas and Whitney Mercilus with dog trainers

Former NFL players Joe Thomas and Whitney Mercilus pose with Randolph Air Force Base canines and their trainers. (USAA)

Alongside Houston Texans legend Whitney Mercilus, Thomas not only learned what the canines and their trainers do on a daily basis, but they got to see just how fast the dogs are during the "K-9 forty."

Thomas and Mercilus put on dog training suits that allow the canines to replicate real-life scenarios of taking down perpetrators. The extreme padding lets the dog bite on command, and it won’t let go until directed to do so. 

DARRELLE REVIS, JOE THOMAS HIGHLIGHT PRO FOOTBALL HALL OF FAME CLASS OF 2023

"My first start was against James Harrison and the Steelers. I knew he had the potential to hurt me, but I was pretty sure he wasn’t going to eat me," Thomas said jokingly to Fox News Digital. "I was not exactly sure in that moment when the dog took me down if he wasn’t going to eat me."

Thomas and Mercilus both ran away from the dog, and after getting a head start, the trainer commanded the dog to sprint after the former NFLers and take them down. 

"It was really cool for me and Whitney to see it up close, put the dog suit on and we got to try to run away and try to act like perpetrators as well as we possibly could," Thomas explained. "I’m not sure I would’ve survived it had I not been wearing that dog suit."

Joe Thomas looks up

Left tackle Joe Thomas of the Browns kneels during timeout in the New York Giants game on Nov. 27, 2016, at FirstEnergy Stadium in Cleveland, Ohio. (Nick Cammett/Diamond Images/Getty Images)

Thomas added that he thought he got a little farther than Mercilus during the training exercise, but in the end, they both hit the floor quickly. 

While it was an exhilarating experience, it was one where Thomas learned a lot about an area of the armed forces he now has an extra appreciation for. 

BROWNS' NICK CHUBB ON RUNNING BACKS' FREE-AGENT MARKET: ‘WE’RE KIND OF HANDCUFFED WITH THE SITUATION'

"Seeing what it’s like being a working dog trainer, and see what their daily life is like, was really cool," he said. "They got a cool job and they work hard and we appreciate everything they do to keep all of us safe. It was cool seeing what those dogs can do – how powerful, how fast they are, how good their noses are."

Thomas will be inducted into the Pro Football Hall of Fame on Aug. 5 in Canton, Ohio, forever enshrined with his allegiance to the Browns, who play just an hour north. 

Joe Thomas speaks in microphone

Former offensive tackle Joe Thomas addresses the crowd after being inducted into the Browns Ring of Honor during halftime, Sept. 18, 2022, in Cleveland. (Akron Beacon Journal)

CLICK HERE TO GET THE FOX NEWS APP

And while Thomas spent numerous seasons as an All Pro and Pro Bowl honoree defending his quarterbacks from some of the biggest and baddest defensive ends in the NFL, like Mercilus, he’ll admit he was no match for those dogs at Randolph Air Force Base.