Norris caught a bullpen session on Tuesday and felt good after, and he took batting practice prior to Wednesday 's game. Assuming all goes well, Norris will start Thursday to provide an extra right-handed bat against Astros left-handed starter Erik Bedard.
"Obviously, my back's not 100 percent," Norris said. "But I'm able to do every movement without any pain. It's just a little bit of back tightness and that's it."
Melvin opted not to pinch-run for Tuesday's starting catcher, Stephen Vogt, when he reached first base in the ninth inning with the A's trailing by one run, but the A's manager said that was more because of Oakland's limited bench than Norris' health.
Melvin inserted Coco Crisp to pinch-run for first baseman Nate Freiman in the eighth, which resulted in a everyday third baseman Josh Donaldson switching to first base on defense in the ninth and Alberto Callaspo coming into the game to play third base.
"I had no one to pinch-run for him," Melvin said.
Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.