INDIANAPOLIS -- Indianapolis Colts tight end Jack Doyle views the friendship as his chance to be a kid again. But 7-year-old Brody Stephens looks at Doyle as a motivating factor in a battle in which the odds are stacked against him.

Stephens was in remission for four years and 11 months from acute myeloid leukemia when he was diagnosed with acute lymphoblastic leukemia last December. Doctors told Stephens' parents that their son only had about a 40 percent chance of beating the leukemia.

That's where Doyle comes into the picture. Viewed as a long shot to make the NFL coming out of Western Kentucky, Doyle is now headed into his fourth season. He has developed a special bond with Stephens, visiting him in the hospital at least once a week and talking with him daily via FaceTime.

Colts tight end Jack Doyle and Brody Stephens at Riley Children’s Hospital in Indianapolis. Courtesy of Jason Stephens

"It's tough," Doyle said. "Brody, he brings me so much joy that it gets lost in all this. To see how tough he is, he fights through things and bounces back like it's nothing. He attacks every obstacle that he's already overcome and every obstacle that he's going to overcome. That's amazing."

Doyle met Stephens while on vacation in Florida in March 2014. Stephens and his three brothers were playing football on the beach when Doyle joined them. The tight end spent a "couple of hours" playing catch with the boys, and he ended the day by autographing a football and giving it to Brody.

Stephens appeared to be on his way to being cancer-free. But symptoms of something wrong -- bruising and getting tired easily -- surfaced last fall. Stephens' father, Jason, was tipped off that something wasn't right during a basketball tournament.

"Brody doesn't like being taken out of a game no matter if they're winning or losing by 20 points," Jason Stephens said. "He took himself out two minutes into the game and didn't want to go back in no matter what. I just knew something wasn't right. He was diagnosed with AML in December. Brody is the only kid at Riley [Hospital for Children at Indiana University Health] that they've seen beat one form of cancer to get another form."

Doyle, through a mutual friend, heard the news about Stephens and immediately began visiting him on a regular basis and having phone conversations with him that range from five to 30 minutes.

Stephens is in the midst of 28 straight days of 24-hour chemotherapy. Once he finishes he'll have a bone marrow biopsy to see if the leukemia is in remission. Stephens will then have a stem cell transplant if he's in remission.

"We're very honest with Brody," Jason Stephens said. "He knows he basically has a 40 percent chance to make it. Our family knows it, too. That's another reason he hangs out with Jack. With my boys, I try to keep things together sports-wise. Jack was a long shot, probably had less than a 40 percent chance to make it in the NFL."

Doyle, who went to high school in Indianapolis, was claimed by the Colts off waivers from Tennessee in September 2013. He's in line to be starter Dwayne Allen's backup next season.

Doyle's time with Stephens isn't a pity party. They toss a football inside Stephens' room. They play basketball together, watch movies and play video games. Doyle even lifts weights with Stephens during his physical therapy sessions. Stephens' energy and appetite are better on some days than others, but he always seems to have fun with Doyle.

"It's totally fun kid stuff," Doyle said. "I taught him some games we can do in the room together. The motivation he gives me to fight through every day, and he enjoys every day by having fun with it. It really does bring me joy."

Stephens added, "We talk a lot of sports and watch my favorite movie, 'Space Jam,' a lot. I watched 'Rookie of the Year' for the first time with Jack."

Stephens has more than 5,500 followers on his Facebook page. Colts coach Chuck Pagano, who battled leukemia in 2012, sent Stephens a letter. The entire Purdue men's basketball team visited him in the hospital the day before their game against Indiana in February.

Stephens was supposed to watch the Indiana Pacers take on LeBron James and the Cleveland Cavaliers in February, but he could not attend because his immune system was compromised too much to be around large crowds. A doctor at Riley Hospital went to the same high school as James and was able to pass along Stephens' news to the superstar. James wrote Stephens a letter and sent him one of his bracelets that said "I Promise" on it.

Letter from LeBron James to Brody Stephens. Courtesy of Jason Stephens

Stephens confidently said he plans on being able to watch James in person and continue to build on what's an already strong friendship with Doyle.

"I'm going to beat this," Stephens said.

When told of Stephens' comments, Doyle said, "I wouldn't expect to hear anything less from him."