Team internist Dr. Stephen Cleves and medical director Dr. Tim Kremchek made the diagnosis on Votto after results from an audiologist came back. Votto learned the results Wednesday night.
"I'm just glad they found what it was. I'm thankful and grateful," Reds manager Dusty Baker said. "There was a lot of stuff floating around out there. A lot of neighborhood doctors. I got more calls from people that knew what it was."
Concern for Votto grew as his absence prolonged. Comparisons were starting to be made with former Reds slugger Nick Esasky, whose career was cut short in 1990 with the Braves by vertigo.
Votto was obviously the most concerned of anyone, but said he's been free of dizzy spells for several days.
"It was such a shock, especially staying in the hospital and staying overnight," said Votto, who experienced ear infections as a child. "Finally getting the results back not only gave me peace of mind, but a sense of confidence. You just feel better altogether."
"All other testing was normal," Reds head trainer Mark Mann said. "The only thing that came back irregular was the audiology tests that indicated he had an inner ear infection that was secondary to the upper respiratory infection he had 10 days ago, which I get from Dr. Cleves, is a common occurrence."
During the previous homestand, Votto missed four starts because of the flu -- which also knocked down teammate Brandon Phillips for a couple of games. In his first game back as a late-inning replacement on May 10, Votto hit a homer in his first at-bat, then took the team flight to Phoenix to start a six-game West Coast road trip.
In the May 12 game at Arizona, Votto left in the middle of an inning when he became dizzy. It happened again Saturday vs. the Padres, and then he was too dizzy to fly home Sunday with the team after not playing.
"That was probably the worst of all of them," Votto said.
The 25-year-old was admitted to the Scripps Clinic in San Diego for testing Sunday and underwent more tests the past several days after he returned to Cincinnati.
"He flew after the sickness and upper respiratory infection from Cincinnati to Phoenix," Mann said. "That's probably what set things off or started the symptoms. And then flying from Phoenix to San Diego. That's why he ended up having the symptoms again on Saturday. This should be something that resolves itself over the next few days."
One question that immediately sprung to mind was why wasn't something like an ear infection spotted sooner?
"When talking about the inner ear, there is a lot greater in depth testing that needs to be done by an audiologist to really look at his balance and inner ear fluid," Mann said. "It's a completely different battery of tests than [an ear-nose-throat doctor] would do."
In 32 games this season, Votto is batting a team-high .366 with five home runs and 27 RBIs.
"We have a lot of great players on our team, so it's hard to say he's our best player. He's the best hitter on our team," Phillips said. "We miss Joey and I hope he's better. I miss my next door neighbor to my left [at first base]."
Votto did a light workout of running and lifting weights Wednesday and did likewise Thursday, plus hit in the Reds' indoor cage. If all remains well, Votto will do a full pregame workout with the team Friday. His return is still considered a day-to-day decision.
The Reds have lost five of their past six games and could use Votto's bat back in the lineup.
"Sitting on bench seeing the game, I was champing at the bit and I wanted to get in there today," Votto said. "Mark's common sense kept me out.
"Today I felt great. Getting some running in and some hitting more than anything lifted my spirits."