Most notably, St. Vincent Health dedicated Peyton Manning Children's Hospital in 2007, and Manning has been a regular visitor in the facility since.

"No publicity, no fanfare, he'd just come here and do the job and talk to the family, the patient and encourage them," said Vince Caponi, CEO of St. Vincent Health. "It did make a difference in people's lives, and he will continue to make a difference in people's lives."

Caponi told RTV6 there are no plans to rename the hospital, and said he's confident Manning will remain involved.

"There's something else we can name after Andrew Luck," Caponi joked when asked about future plans. "We fully expect we'll have to be more scheduled with (Manning's) time and commitment here. We'll have to sit down and talk about that."

Patients told RTV6 they feel the affect of Manning's generosity.

"He's a great icon for Indianapolis," said patient Shannon Lawler. "It's sad to see him leave the Colts, but I think he will stay with Indianapolis."

Manning also supports the PeyBack Foundation, an organization he founded in 1999 that has donated more than $4.3 million to youth organizations in Indiana, Tennessee and Louisiana.

Executive Director Elizabeth Ellis was unavailable for interviews Wednesday, but Manning released a statement saying he was committed to supporting youth-based organizations through grants and programs

Members of the PeyBack Foundation Resource Council told RTV6 they're unsure what Manning's involvement will be in the coming months and years.

"I would certainly hope as long as Peyton is able to support it, it gets its support primarily from Peyton," said Joe Slash with the Urban League, who is also a member of the foundation's resource council. "Extending his career is certainly something the foundation would benefit from."

The foundation, for example, helped feed 25 families in need on Thanksgiving.

"I'm sure he will continue to be very generous," said Indianapolis Public Schools Superintendent Eugene White, who is a member of the PeyBack Foundation Resource Council. "I think he will still have a presence when he leaves."

City leaders said they're sad to be losing such a champion for Indianapolis.

When the Indianapolis Convention and Visitors Association needed someone to voice a video extolling the virtues of Indianapolis, they tapped Manning, who did the job for free and in one take.

"We're a winning city. We're a competitive city. We're a clean, crisp family friendly city. Peyton Manning epitomizes that not only in his actions on the field, but off the field," said Chris Gahl with the Indianapolis Convention and Visitors Association. "From a marketing perspective, we say thank you for arguably being one of the top 10 individuals in the last 30 years that have helped the city grow."

But it's his generosity that has distinguished Manning from other legendary Hoosier athletes.

"With the Peyton Manning Children's Hospital. The PeyBack Foundation. The way he carried himself. The way he always spoke so highly of the city of Indianapolis," said Bill Benner, a former sports columnist. "Just in so many ways other than being a great, great, quarterback, we fell in love with the guy."