Peyton Manning, Pat McAfee Mourn Jim Irsay's Death

Tributes have been pouring in following the shocking death of Indianapolis Colts owner Jim Irsay ... with plenty of former players, coaches and loved ones taking time to remember the 65-year-old -- including the team's Super Bowl-winning quarterback, Peyton Manning.

The 49-year-old took to his Instagram to speak on Irsay's passing ... calling him an "incredibly generous and passionate owner, and I will always be indebted to him for giving me my start in the NFL."

"His love for the Colts and the city of Indy was unmatched. His impact on the players who played for him will not be forgotten."

Tom Brady left a comment on Peyton's post, responding with an "♥️🙏🏽RIP♥️🙏🏽

Manning was selected by the Colts the year after Irsay became the team owner ... taking the reins after the passing of his father, Robert Irsay. The Hall of Famer went on to spend 13 years with the team, helping bring home the Lombardi Trophy in 2007.

Pat McAfee posted a lengthy message to his former boss and friend after the news broke ... saying he was one of the lucky players to have had a relationship with Jim.

"He battled his demons, as we all do but, God blessed Jim Irsay with an abundance of compassion.. he wanted to give back/help everybody and everything he saw or knew about. Putting a list together of all of the causes/things/people that he's given to would be an impossible task.. probably well over $100,000,000."

T.Y. Hilton -- who spent 10 seasons with the franchise -- said he will "forever hold our talks close to my heart" in his statement. The team's ex-head coach, Tony Dungy, said Irsay's presence "Was a blessing to his players and staff."

"He loved people and did so many things for others -- more things than you could imagine. I miss him already."

Irsay passed away in his sleep Wednesday. He is survived by his daughters Carlie Irsay-Gordon, Casy Foyt, and Kalen Jackson, his ex-wife, Meg Coyle, and 10 grandchildren.