Raiders third-year wide receiver Chaz Schilens visited a knee specialist Monday about the prospect of having surgery in the coming days, coach Tom Cable said.
Cable said Schilens' knee injury probably is the result of his "overcompensating" for the sore left foot that has bothered him the past year.
Schilens has missed numerous practices throughout training camp while recovering from a second operation on his foot in January. That operation was a follow-up to the one performed on the same foot in August, when Schilens broke the fifth metatarsal bone in a joint practice with the 49ers.
Cable said he hopes that the procedure, if needed, is a simple one and won't sideline Schilens for too long. The season opener is Sept. 12 at Tennessee.
"I'm very concerned," Cable said in a conference call. "It's been a tough road for him. We get through the foot thing now, and something else has kind of reared up on us. We'll take care of it and get him back as soon as we can."
Schilens missed the first eight games last season because of the foot injury. He returned for the final eight games and caught 29 passes for 365 yards and two touchdowns.
He also battled injuries his rookie season in 2008, though he appeared in all 16 games.
Schilens arrived at camp confident his injuries were behind him, and he was prepared to nail down the No. 1 spot.
"Yeah, I feel good," Schilens said July 27.
His expected absence means second-year players Louis Murphy and Darrius Heyward-Bey probably will enter the season as the starters for the second straight year.
Murphy and Heyward-Bey also have struggled with their health the first three weeks of camp. Murphy suffered a concussion early and missed several days because of persistent symptoms. He also missed time because of a foot injury. Heyward-Bey missed most of practice last week with what Cable termed "fatigue."
"I don't think it's going to be a setback," Heyward-Bey said. "I will be ready to go as soon as everything starts feeling right. The important thing is Tennessee. That's the first game of the season."
Murphy led all Raiders wide receivers last season with 34 receptions for 521 yards and four touchdowns.
The addition of rookie Jacoby Ford and the continued development of Johnnie Lee Higgins, Todd Watkins and Yamon Figurs give Cable reason for comfort.
"The group is developing," Cable said. "Hopefully, we don't lose Chaz for any time. But if it does happen, I do think we're developing that group."
Notes: Center Samson Satele underwent X-rays on the ankle he injured against the Chicago Bears on Saturday, Cable said. The results won't be known until today. Satele missed the rest of the game and was replaced by Chris Morris. ... The Raiders resume practice in Napa today with one session. They will practice there through Thursday before breaking camp. They will shift operations to their year-round facility in Alameda on Friday and kick off practicing there Monday. ... The Raider Nation Celebration is Friday at Frank Ogawa Plaza in Oakland from 4-6 p.m. There is no charge for admittance.
