"I feel all right. I just tweaked it," Norris said after the game, a 9-5 Oakland win. "Anybody that has back problems knows they can come out of nowhere. My muscles aren't spasmed out or anything like that. I wouldn't suspect anything more than about a day off or so.
"My pain tolerance is high. It requires quite a bit for me to not be able to play."
Norris has a history of back issues, but he has never missed significant time. He was replaced behind the plate by Stephen Vogt, who went 2-for-3 with an RBI.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.