Raiders: Head injury keeps Langston Walker off field

On Wednesday morning, Langston Walker woke up without a headache and decided it was a good day to try to play football again. So, 10 days after the Raiders right tackle took a hit in the back of the head and lay unconscious for 30 seconds on the Oakland Coliseum field, he put his helmet on and went back to work.

Walker's concussion had not gone away, however, as once practice started, his headache returned and he was done. Back to the locker room. Back to sit on the bench in front of his locker and wait for his head to clear up, wait to feel like himself again.

"I passed all the tests," Walker said, "now it's just getting rid of all the symptoms. I guess it's up to your body to heal."

The tests are part of the NFL's concussion protocol as the league strives to prevent players with head injuries from returning too soon. Guidelines include newer helmets, tougher penalties for violent hits, and post-concussive physical and motor skills tests for injured players to pass before returning.

Walker, a nine-year veteran who went to Oakland's Bishop O'Dowd High and Cal, heard there were new guidelines but didn't pay too much attention since he hadn't had a concussion since college. But that all changed when he was blocked on an interception return by the Broncos on Dec. 19, the back of his helmet hitting the ground with considerable force.

He came to, was helped to the sideline and spent Monday and Tuesday of last week allergic to daylight and noise.

"I basically laid in the dark - I felt like I was depressed and did nothing," Walker said.

A concussion involves a hit that rattles a part of the brain involved in language processing or motor skills. So, Walker had to pass a test, that all players take before the season and then again upon sustaining a concussion.

"You have one test you actually do, it's on a computer," Walker said. "You take the same test at the beginning of the year, that determines your baseline, and when you get a concussion, you take the test again. And you have to be within a certain percentage of that baseline test to practice and play."

The test includes word-association and reaction times.

"Spatial memory, short-term memory, long-term memory, stuff like that," Walker said. "Very abstract."

Walker failed the test Dec. 20, failed it again Dec. 22 and then passed it Friday. He was cleared by an independent neurologist, giving Raiders coach Tom Cable some hope that Walker could start against last Sunday.

But the headaches persisted. The good news is that after Walker stopped trying to practice Wednesday, the headache subsided. Today, he'll see if he can give it another try.

Cable would love to get the 360-pounder back, but he's in no rush.

"I don't think you mess with the brain," Cable said. "I think you do whatever is necessary to make sure - they have done so much work with the helmets, but the guy has to be right, in terms of his health, and the brain ... you just don't mess with it."

E-mail Vittorio Tafur at vtafur@sfchronicle.com.

This article appeared on page B - 3 of the San Francisco Chronicle