When a Texas football coach with an uncommon blood type and rare genetic condition needed a liver transplant, one of his fellow assistant coaches stepped up to make the biggest play.
For 40 years, John McWilliams has been coaching high-school football. But the offensive-line coach at Houston's Cypress Ridge High School found himself on the defensive when his health declined and doctors at the Mayo Clinic in Rochester, Minnesota, diagnosed him with familial amyloidosis, a rare disease that affects his liver.
"Unlike typical liver diseases where the disease causes the liver to fail, his liver works fine," Dr. John Poterucha, of the Mayo Clinic, told TODAY. "The only problem is the liver makes an abnormal protein and this abnormal protein deposits in other tissues."
Without a liver transplant, that protein threatened McWilliams' heart health, according to Dr. Julie Heimbach, also of the Mayo Clinic.
McWilliams turned to family, friends and coworkers at his high school, where he teaches biology in addition to coaching.
"We were all sitting there," he recalled, "and I kind of said, 'Guys, if anybody has [an] 'O' blood [type], anybody would like to donate a portion of your liver to me, I'll be more than happy to accept it because I need a liver transplant as quickly as we can find a living donor.'"
Among those to hear McWilliams' plea was fellow coach Matthew Beeler, whose O-positive blood type made him an ideal candidate.
"You know, [in] football, we say anytime there's an injury or something happens, it's always next man up," Beeler said. "My number was called. My name was called to do something great. So I felt compelled and felt that it was my calling."
After losing 30 pounds to match McWilliams' body-mass index, Beeler — a newlywed — flew with his wife, Rozana, to Minnesota so he could undergo tests at the Mayo Clinic.
"Her being so selfless is [why] we kind of put our plans on hold," Beeler said. "We were married in January, and that's kind of really when the weight loss and the process really kicked off...We've kind of put things on hold and I joke with her that she doesn't really need a honeymoon, she's got to come to Rochester, Minnesota twice."
Since a healthy liver can regrow itself, Beeler could donate most of his liver to McWilliams.
Surgeons removed 63 percent of Beeler's liver, which was examined, placed on ice, and rushed to McWilliams' operating room to complete the transplant. Doctors hope the new liver will stop production of the harmful protein in McWiliams' body.
But the transplant chain doesn't end there. A third person, a stranger named Rudy Myers, was slated to receive McWilliams' old liver, which could work for decades in the body of an older person.
"It's [taken] 60 years almost for it to create a problem in me," McWilliams said. "And most people don't live to be 110, 120 years old. So, yeah, they can survive with my liver up until, you know, the time."
Myers, who has liver cirrhosis, has been waiting for a transplant for more than a year. Just days ago, he learned that he'd receive McWilliams' liver, considered a “domino” transplant because of its successive nature.
"I had no idea what a domino was other than a pizza," Myers said with a laugh.
All three men have weeks of recovery ahead, but thanks to two generous liver hand-offs, they're favored to win.
More than 100,000 Americans are in need of a life-saving organ transplant, and only a small percentage of available organs are in play. Find more information about becoming a living donor here.
Follow TODAY.com writer Chris Serico on Twitter.