"We were lucky the way it worked out," Joey said. "I was just happy to do what I could."
The transplant was a success, and Richie returned home a few weeks later. He was required to wear a surgical mask to help protect him from infection and doctors said he probably wouldn't be able to go out in public for several months, Dick Mitchell said.
But Richie made a stunningly swift recovery. He was in class for the first day of school in September.
"Doctors looked at the progress he made in a short time," Dick Mitchell said. "They felt it would be better for him psychologically to be around his own friends than sitting in his room. That was a big boost for him."
Though he was in no shape to play football, Richie was made a team captain and cheered from the sideline during their championship season.
"It was frustrating, but I was happy for all my friends," he said. "I played with them for a long time. Cheering them on was great."
Mitchell figured that if he was going to play football again, it would probably have to be at a community college.
But after last season, Ayala's coach at the time, Lou Randall, asked Mitchell whether he would be interested in applying for a hardship waiver that would allow him to play in 2003. Though he had enough credits to graduate, Mitchell decided one more season of high school football was worth returning for a fifth year at Ayala.
The Southern Section granted the hardship waiver and Mitchell participated in spring football after getting medical clearance.
Meshing with his younger teammates presented another challenge. When Mount, who was an Ayala assistant, was named head coach after Randall took the coaching job at Riverside North last spring, he quickly noticed that Mitchell separated himself from everyone else.
"The team sat on one side of the room," Mount said. "Richie was on the other side by himself. He hadn't bonded with those guys because they looked up to him."
Mitchell said it didn't take long to break down those barriers.
"It's fine now," he said. "We're all pretty close."
Nick Ketelsleger, a senior lineman, said it was strange at first to have Mitchell on the team.
"He grew up playing with all these older guys," Ketelsleger said. "But it's been fun having him here."
Mount, 51, said having Mitchell this season has been invaluable because he leads by example.
"He's one of the most dependable kids I've ever coached," Mount said. "He never misses a practice, he's always punctual. He always gives 100%.
"He's like having a coach on the field."
When Mitchell finally did step on the field again for Ayala's season opener against Santa Maria Righetti, it was an emotional moment.
"It was probably one of the best feelings you could have," he said. "To finally be there, it was a big thrill."
Despite everything he's been through, Mitchell has no intention of taking it easy or playing it safe in life.
He hopes to become a firefighter, a job that took on added significance in the last month in Southern California because of the wildfires.
"I have a lot of respect for those guys," he said. "They put their lives on the line."