Newbury Park High tailback Walter Thomas will miss at least five weeks of play after undergoing arthroscopic knee surgery, Coach George Hurley said.
Thomas, a senior who led the team with 647 rushing yards last season, injured his left knee late in the first quarter of Newbury Park's 21-6 loss to Chaminade on Friday.
Initially Newbury Park believed Thomas, who rushed for 50 yards in eight carries, would return in two weeks.
"It's more serious than we thought," Hurley said. Surgery was performed Saturday.
Thomas' injury is one of many that has decimated Newbury Park.
Starting fullback Jeff Buchanan did not play against Chaminade because of a back injury and starters Sean McKeown (lineman) and Kyle Bybee (tight end) were treated at a hospital for heat exhaustion.
Four of Newbury Park's six returning starters are sidelined, and its 40-man roster had dwindled to 28 by Monday.
"You name it, we have it," Hurley said.
Hurley said seniors Dave Roberts and Sean Pence will fill in for Thomas and Buchanan when the Panthers face Ventura on Friday.