FLAGSTAFF, Ariz. — The Hopi High School football team was in the midst of its best regular season ever, going 9-1 into a playoff game against a top-seeded team. Facing a complete shutdown, senior wide receiver Charles Youvella caught a pass and scored the team’s only touchdown in the third quarter.

Well into the fourth quarter in Saturday’s 60-6 loss to Arizona Lutheran Academy, Youvella fell hard on his head and collapsed a couple of plays later. He died Monday at the hospital of a traumatic brain injury, the Arizona Interscholastic Association said.

Youvella’s death was a somber end to a football season in which the players had grown more enthusiastic about the game on the small northeastern Arizona reservation. It also comes at a time when head injuries in football are attracting attention at all levels of the sport. The Institute of Medicine and National Research Council two weeks ago called for a national system to track sports-related concussions and answer questions about youth concussions.

The report said 250,000 people age 19 and younger were treated in emergency rooms for concussions and other sports- or recreation-related brain injuries in the country in 2009. That was an increase from 150,000 in 2001.

A community memorial is planned Wednesday evening at the high school auditorium in Keams Canyon. The high school has grief counselors on hand and will release students early, if needed, to attend funeral services later this week in Polacca.

Youvella died with this family at his side. His father, Wallace Youvella Jr., is the school’s athletic director.

School spirits were high earlier Saturday as the boys and girls cross country teams won state titles, the boys extending the longest-running streak of consecutive wins in the nation. About 250 of the Bruins’ fans watched the football team take on Arizona Lutheran in the first-round playoff game.

Head football coach Steve Saban said Youvella was part of a batch of kids who had been playing for him for years and had vowed to put in the work needed to become the standout team in football, which isn’t the most popular sport at the school. The only loss the Bruins had this season was in overtime.

“We had just a beautiful season, best record in school history,” he said. “Down there in the state playoffs, it was just a great experience for the kids. And then the terrible tragedy. It was just like a bad dream.”

The Hopi radio station, KUYI, was doing its first live remote broadcast of an Arizona state playoff game when Youvella was hit. Broadcaster Stan Bindell told listeners that Youvella went down but the extent of his injury wasn’t known. The game resumed about 45 minutes later after Youvella was taken to the hospital.

“It’s kind of quiet here right now,” fellow broadcaster Clark Tenakhongva said over the radio. “But I told the people back here on Hopi, please have him in our prayers and think about him, that it’s not something serious, that he will return back to football.”

Hopi High School principal Glenn Gilman was on the sidelines encouraging Youvella throughout the game. The Hopi players were tired and some of them were cramping up, but they were unrelenting in moving forward, Gilman said.

“Charles really had a strong will and just never gave up, especially when it came to athletics,” Gilman said.

Gilman said the initial call from an athletic trainer from Arizona Lutheran was that Youvella, who also played basketball for Hopi High School, had suffered a concussion. Emergency responders arrived about 15 minutes after Youvella collapsed, he said.

Game officials kept the clock running under a rule that gets implemented when a team is up by 42 points. The Arizona Interscholastic Association has no mercy rule, nor does it match up teams based on their size.

Chuck Schmidt, the AIA’s associate executive director and chief operating officer, said the association would be gathering details from the medical examiner and officials on site, and looking at its own response.

“I can’t explain why it happened,” he said. “We have too many people drawing conclusions as to a play. Our focus right now is the family, assisting them in the grieving process and making sure they have time to do that.”

Schmidt said an account will be set up to help defray costs for the Youvella family. Hopi High School also is accepting donations.

Arizona Cardinals wide receiver Larry Fitzgerald reached out to fans on Twitter with a picture of Youvella, asking them to pray for the teen’s family, friends and teammates.

“The heart that he played with, the tenacity, the passion — that spoke for itself,” Saban said. “The young kids, especially if they were bigger kids, they’d see this little, tiny kid doing what he’s doing. Charles led by example.”