Reimold, batting fifth, immediately dropped to the ground and was facedown for several minutes while a hushed crowd watched as Orioles trainers tended to him.
The 28-year-old was taken to Peace River Hospital, and CT scans came back negative, although he does have a loose tooth.
"The lowlight was Nolan getting hit and the highlight was finding out he didn't have a break," Orioles manager Buck Showalter said after the Orioles and Rays played to a 3-3 tie in 10 innings. "I didn't like his chances.
"He's been through a lot. That's what was going on through my head. He was going to get a chance to play this year, and everything is in order, and standing out there with him, your heart's in your throat for no other reason than his health."
The incident affected both teams, and especially Cobb, who got Reimold's phone number and plans to check up on him.
"It's probably the worst feeling you can have as a pitcher, seeing something like that and being the cause of a guy taking a step back in his career possibly," Cobb said. "It's just something you never want to see on the baseball field, and when you're the cause of it, it's a feeling you can't describe."
Cobb recovered to pitch three scoreless innings, giving up two hits and two walks in his first start of the spring. Cobb had season-ending surgery in August to remove a blood clot as well as blockage in his right rib.
Baltimore right-hander Jake Arrieta, making his first start since his own season-ending elbow surgery in August, pitched two scoreless innings for Baltimore, giving up only a walk and striking out one.
"That's really the best I've felt, not only this year, spring training, but I think in my entire professional career altogether," Arrieta said. "I feel like I could have thrown the whole game today — no soreness, no tightness. Just an incredible feeling now."
Notes: The Rays named RHP James Shields their opening day starter Friday. ... X-rays were negative for Rays SS Sean Rodriguez (left index finger sprain) and he should be playing in 2-3 days. ... Rays 3B Evan Longoria (bruised hand) said he felt great after taking batting practice and fielding drills Friday. ... Orioles RHP Jason Berken (strained left hamstring) suffered a setback, Showalter said. It's unlikely he'll be able to start his season with Baltimore. ... Orioles 3B Mark Reynolds, C Taylor Teagarden and RHP Matt Lindstrom all have back tightness and did not travel with the team Friday. ... C Ronny Paulino, whose arrival has been stalled by visa issues, could report Saturday, Showalter said.