The doorbell rang.

Antonella Tripiciano was expecting it. Her son, Nico Oneto, wasn't.

A week after Nico returned home from his latest extended hospital stay, a surprise awaited the 10-year old.

Tripiciano turned to Nico and said, "You remember that man that plays for Alabama? He's at the door."

After some urging from his mother, Nico went and opened the door. Standing there was Tide All-American defensive back Minkah Fitzpatrick and his father.

"His jaw just dropped," Tripiciano said. "The smile on his face and the shock like 'Is he really at my house?' It was a priceless moment."

Fitzpatrick and Nico first connected in September, shortly after the Alabama standout learned of Nico's ongoing battle with cancer. Dec. 14 was the first time they met in person, when Fitzpatrick was back home in New Jersey.

This young boy and this friendship are why Fitzpatrick has had "Nico" written on his elbow sleeve for several games this season.

Fitzpatrick has encouraged Nico, and Nico has inspired the Tide's star safety.

'It felt like a brick hit me'

The nurse at Arleth Elementary School in New Jersey called Tripiciano Nov. 30, 2014. An 8-year old Nico had a 102-degree fever and needed to be picked up.

It didn't seem overly serious at first. Nico tested positive for strep throat the next day and was put on an antibiotic. He didn't get better, though. Two rounds of blood work led to Nico's pediatrician recommending that Nico go see a local oncologist, a doctor who treats cancer.

Tripiciano remembers asking, "An oncologist? Are you telling me my son has cancer?"

"No," the pediatrician responded, "We just need to look at a few things."

You can see "Nico" written on Minkah Fitzpatrick's elbow sleeve during Alabama's win over Kent State in September.

Nico underwent a bone marrow biopsy the next week. Ninety minutes following the procedure, a nurse took Tripiciano to a room with three doctors. One delivered the news, "Your son has cancer. He has acute myeloid leukemia."

Acute myeloid leukemia (AML) starts in the bone marrow and often quickly moves into the blood. Only 26 percent of people with AML live more than five years, according to the Leukemia & Lymphoma Society.

Making it even worse is that Nico has a rare form of AML that is very aggressive. Patients with this form of AML are more likely to relapse after remission.

"It felt like a brick hit me," Tripiciano said. "It was like a tractor trailer hit me and ran me over. I was a mess -- tears, everything."

An ongoing battle

Nico underwent his first bone marrow transplant May 6, 2015 after three unsuccessful cycles of chemotherapy that caused him to lose his hair, made him consistently sick and led to him dropping from 122 pounds to 91.

Earlier this year, Tripiciano began to suspect the cancer was back. Her fears were confirmed in August. As tough as Nico has been through the entire process, it was difficult news to bear.

"I don't want to do another transplant," a crying Nico told his family. "If God wants to take me, then why doesn't He just take me? Why's He making me suffer?"

Tripiciano, consoling her son, told him, "I think He's just giving you another obstacle that you need to overcome."

Nico was readmitted to the hospital in mid-September and underwent his second bone marrow transplant a month ago. Before the operation, doctors gave Tripiciano a grave warning. "Brace yourself," they said. "He might not come home."

"As far as statistics go, they thought the toxicity in my child would have been so bad that he would have never made it," Tripiciano said. "He proved them wrong again."

Nico returned home Dec. 5 and was able to spend Christmas with his family. There's still concern, though. The donor for the first transplant was a perfect match. His mom, the donor for the second transplant in November, was only a 6 out of 10 match.

"This is not a cure for my son," Tripiciano said, beginning to cry. "They make it very clear to us to just enjoy life because it can change in a heartbeat. Unfortunately, with everything that Nico has endured already, we have no options left if he does relapse and the leukemia comes back. We still have like a good three or four months that his body can reject my cells, so that's still in the back of my head. If that happens, there's nothing they can do for him."

After returning home, Nico told his parents that he didn't want any presents for Christmas. He insisted they instead buy gifts for other children at the hospital. "This year's all about giving," he told his mother. "Everybody gave to me, and I want to give back to them this year."

Tripiciano and her fiance obliged his request, buying iTunes gift cards, board games, dolls, Legos and more for children on Nico's old floor in the hospital.

'Keep fighting'

Fitzpatrick's mom, Melissa, first heard about Nico in September when she was in attendance for Fitzpatrick's 9-year old brother's youth football game.

"I was really upset because I didn't have any money on me at the time, and it bothered me that I couldn't give anything," Melissa Fitzpatrick said. "But I came back home. And on Facebook, somebody put Nico's picture up, and I was like 'Thank God' that we have a way that we can reach out."

After going through a Facebook page that provides updates on Nico, Melissa told Minkah about Nico and reached out to Tripiciano.

"I just told her that their story really touched my family and that we're going to continue to pray for them," Melissa said. "And I asked if she would mind if Minkah reached out to Nico because we thought that might put a smile on his face."

The families have gotten close ever since. The two moms talk regularly about their sons. Minkah periodically sends inspirational messages for Nico.

The day they met, Nico wasn't feeling well. That changed when Minkah arrived.

Minkah and his father were there for more than two hours, praying, eating pizza and playing with the family. Nico taught Minkah how to play Uno. Minkah gave Nico a pair of football gloves, and the two took pictures together.

After Minkah left, a smiling Nico said, "Mom, that was cool. A famous person came to visit me."

Nico keeps the gloves he got from Minkah in a Ziploc bag. "He says that no one can go near them," his mom said laughing.

Before leaving that day, Minkah told Nico something he's said to him several times since they first connected: "Keep fighting."

*** Follow the Nico's Ninjas Facebook page to keep up with Nico's fight against cancer.

*** Click here to make a donation to Nico's Acute Myeloid Leukemia Fund.