Peyton Manning Opens Up About Demaryius Thomas' Death: 'It's Been Really Tough'

Peyton Manning is paying tribute his late Denver Broncos teammate Demaryius Thomas.

Manning revealed that it was no coincidence his stint as the Broncos' quarterback from 2012–2015 overlapped with Thomas's eight-year tenure as a wide receiver for the NFL team from 2010–2018: "He was a big reason why I came out here to play," he told the Broncos' official site on Sunday.

"I knew what he had done in just two years, but I also knew what he was capable of doing. That was a big part of the attractiveness for coming to play for the Broncos," he continued. "So, for so many reasons, I'm very indebted and thankful to Demaryius."

Thomas, 33, was a "special and unique guy," said Manning, 45. "Obviously an incredible player — dependable, accountable, tough, hard-working, unselfish. All the things you want in a great teammate … much less an incredibly talented receiver."

He continued, "Off the field, he was as good a person as he was a player. [He was] very giving to all his teammates' charities, great with all the players and families — coaches' families and kids."

Manning, who played with the Indianapolis Colts for 13 years before signing with the Broncos as a free agent, acknowledged that the days since Thomas's death have "been really tough. Our thoughts and prayers are with his family. He will be dearly missed. He was great to my kids, great to my family — which is more important than any touchdown he ever caught for me."

Thomas, who last played with the New York Jets in 2019, was found dead in his Atlanta, Georgia, home Thursday evening from what police believe to be a medical issue, Officer Tim Lupo, Roswell Police Department public information officer, confirmed to PEOPLE.

"Preliminary information is that his death stems from a medical issue, and our investigators currently have no reason to believe otherwise," Lupo said in a statement.

Though police did not specify the medical issue, Thomas' cousin, LaTonya Bonseigneur, told the Associated Press that his family believes he died of a seizure before they were notified by police around 9 p.m. local time.

"He had been suffering from seizures for over a year, and we believe he had a seizure when he was showering," Bonseigneur told the outlet. "We're not sure when he died. We just spoke with him yesterday."

She continued, "He was alone and a friend couldn't get hold of him, so he called his driver, who has a key because of these seizures, and he went into his home and found him in the shower."

Following the news of Thomas' death, the Broncos released a statement sending condolences to his family that began, "We are devastated and completely heartbroken."

The statement continued, "D.T. was beloved by our entire organization, his teammates and coaches, and our fans. Recently retiring as a Bronco, we were very much looking forward to celebrating Demaryius for years to come as one of the greatest players in franchise history."