Raiders WR Louis Murphy has been sidelined during training camp because of a concussion he suffered during practice Friday when teammate Nnamdi Asomugha  kneed him in the helmet.

Murphy, who says he had never experienced a concussion, will be held out until he passes a series of tests that show he has recovered, according to Oakland head coach Tom Cable.

As a rookie Murphy posted the best numbers of all Raiders wide receivers — 34 catches for 521 yards and four touchdowns. He is being counted on to play a big role again this year.

Meanwhile, fellow Raiders WR Chaz Schilens sat out practice with a sore left foot. It's the same foot that required two surgeries in the past year to repair damage from a broken fifth metatarsal bone, according to the San Jose Mercury News.

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