Still, when the second baseman hit his head against right fielder Ryan Church's knee Friday in an attempt to catch a foul ball along the right-field line, it looked bad.
Walker temporarily lost consciousness, walked off the field and stayed at a nearby hospital's intensive care unit for tests and observation. When he popped into the clubhouse a few hours before Saturday's game against the Oakland A's, teammates greeted him with, "How ya' doing, Walk?"
It was "basically a mild concussion," Walker said. Other than the headache and fatigue from lack of sleep in the hospital, he feels OK. He underwent a CT scan, blood tests and had his blood pressure checked every hour.
"I don't remember getting hit," Walker said, still wearing his hospital ID tag and joking that, "Fortunately, Church has soft knees."
Walker will be evaluated by doctors in Pittsburgh on Monday, manager John Russell said. He hasn't decided on roster adjustments to accommodate the injury just yet.
"We don't need to think about that right now," Russell said. "We'll know more after Monday."
Following the collision, Bobby Crosby moved from shortstop to second base, and Ronny Cedeno entered the game at shortstop. Crosby was slated to start at second Saturday, with Pedro Alvarez at shortstop.
Walker was a triple from the cycle at the time of the injury. He doubled in the first, singled in the third and hit a solo home run in the fifth.