The Cubs did not have results of the test late Sunday, but athletic trainer Mark O'Neal said he was encouraged by how Hairston responded to treatment in the clubhouse. The CAT scan was taken as a precautionary measure.
"He was normal, same old Jerry," O'Neal said. "You're looking for nausea, dizziness, all that kind of stuff, ringing in the ears, and he had none of that."
With one out in the Cubs first, Hairston was plunked on the helmet behind his ear by the second pitch he saw from Correia, who was making his first spring start. Hairston fell to the ground, and lay motionless. Cubs manager Dusty Baker and O'Neal rushed to the plate. Hairston eventually sat up and was able to walk off the field with some help.
"It was frightening at first," Baker said. "You hear the loud sound. They have a new style of helmet. I hope it works. It has less padding and more holes to absorb the shock. It got its first test today.
"It looked like he was out for a minute," Baker said. "At first, he was just there. Then he said he was OK, and wanted to get up."
Hairston was taken to Mesa Banner Hospital for the CAT scan.
"He was completely conscious when we got there [to the plate]," O'Neal said.
Seeing Hairston walk off the field eased some of the concern.
"It's very encouraging," Baker said. "I'm sure he'll probably have a headache."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.