PHOENIX -- D-backs shortstop Didi Gregorius was hit in the helmet by a 93-mph fastball from Rockies reliever Josh Outman in the seventh inning of Arizona's 6-3 loss on Friday night at Chase Field.
The D-backs initially listed the rookie as day to day with a contusion to the right temple, but he could land on the seven-day disabled list if a CT scan reveals he suffered a concussion.
After being struck, Gregorius immediately fell to the ground and was tended to by a member of the D-backs' training staff. He remained on the ground for a couple of minutes, then got to his feet and walked off the field under his own power. Cliff Pennington entered as a pinch-runner for Gregorius at first and stayed in the game defensively.
D-backs manager Kirk Gibson said the 23-year-old underwent a written concussion test upon leaving the game and passed it "with flying colors."
"That shows he has no neurological problems," Gibson said.
After the game, Outman said he hopes he gets the chance to talk to Gregorius before the Rockies leave town.
"The last thing I want to do is hit somebody, especially in the head," Outman said. "I heard on the TV that he's OK, so I'm really happy to hear that. I wish him a full and speedy recovery."
The shortstop has provided a spark to the club since making his team debut on April 18, batting 11-for-27 with six extra-base hits, including a pair of homers. Gregorius is the D-backs' No. 3 prospect, according to MLB.com.
Tyler Emerick is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.