SAN DIEGO -- Even after watching the video of Friday's football game, Mission Hills High School principal and football coaches are puzzled as to what caused senior linebacker Scotty Eveland to collapse.

Eveland staggered off the field during the second quarter against West Hills before reaching the sidelines and receiving medical attention. He underwent brain surgery that night at Palomar Medical Center.

The 17-year-old prep football player is still in critical condition and in a coma, a hospital spokesman said.

Mission Hills Principal Brad Lichtman said Wednesday he could not pinpoint any single play on the tape as a probable cause of Eveland's head injury, the North County Times reported.

Head coach Chris Hauser, speaking publicly for the first time since his player's injury, added that coaches have tried to keep the team focused and unified, according to the newspaper. He said the coaches are at the hospital visiting Eveland every day.

In the meantime, there has been an outpouring of support from neighboring schools, including Mission Hills rival San Pasqual.