Cervelli, who celebrated his 24th birthday on Saturday, was batting against Toronto right-hander Zech Zinicola in the third inning when a fastball hit him in the top of the head.
Cervelli crumpled to the ground and stayed down for about a minute. Blue Jays catcher Jose Molina, a teammate of Cervelli's with the Yankees last season, immediately attended to him.
Standing under his own power after a brief delay, Cervelli was helped off the field by manager Joe Girardi and assistant trainer Steve Donohue. After returning, Cervelli said that he felt "a little dizzy" and had a headache.
"He got up quickly and was like, 'I'm ready,'" Girardi said. "We just kind of slowed him down. You've got to make sure that there's no bleeding there, and that's what the CT scan determined. You just want him to take it slow, because I think your adrenaline is what gets you right back up."
2010 Spring Training - null
Sights & Sounds
Spring Training Info
The head injury is a source of concern for the Yankees. Cervelli suffered a concussion in November, when he was struck in almost the same spot by a batter's backswing in a Venezuelan Winter League game, giving him two concussions in approximately four months.
"It's a concern, any time you start talking about injuries to the head like that," Girardi said. "You're concerned about it. He's feeling OK now, but you worry about it. It's scary."
The Yankees are heading into the season expecting that Cervelli will handle the backup catcher duties behind starter Jorge Posada, one year after he impressed by batting .298 with one home run and 11 RBIs in 42 games (25 starts) over two stints with New York.
Girardi said that he might try to get Cervelli back into a game on Tuesday or Wednesday, but he would not rush.
"He's got to be honest with how he's feeling," Girardi said. "I don't want to send you out there if you're not 100 percent right now. I just can't do it."
Cervelli has had an interesting history in Spring Training games -- in 2008, he suffered a broken right wrist after a home-plate collision with the Rays' Elliot Johnson.
That served as a precursor to a benches-clearing incident between the two clubs a few days later, when New York's Shelley Duncan slid spikes-high into Tampa Bay's Akinori Iwamura.
"It's part of the game," Cervelli said. "You just stand up and keep playing, that's it."
Earlier Saturday, Molina told reporters that the Yankees would be fine with Cervelli as their backup catcher. Molina signed with the Blue Jays as a free agent after the Yankees allowed his contract to expire.
"I know they're in good hands with him," Molina said. "I taught him everything I know, so he should be all right. He's a great catcher. He'll do good; they won't be missing me. He's ready."
With Cervelli out of action for a few days, Girardi said that non-roster invitee Mike Rivera would slide in as the No. 2 catcher on the depth chart, including making Sunday's trip to Fort Myers, Fla., to catch Sergio Mitre against the Twins.