Manager David Bell said Votto has not tested positive for the virus.
“We’re cautious about being able to put him on the COVID IL, which is really a daily thing, until we know more,” Bell told Cincinnati reporters.
Votto was in the original starting lineup to face the Brewers, but showed symptoms.
The six-time All-Star hits just 0.122 without a home run and three RBIs and had played in all 22 Cincinnati games this season. He has struck out 29 times in 74 strokes.
Cincinnati is struggling with the worst record in the major leagues at 3-19. The Reds had lost six in a row and 17 of 18 in the series opener against the Brewers.
The 38-year-old Votto tested positive for COVID-19 in March 2021.
On Monday, Votto linked to a blog post on Fangraphs.com that had this headline: “Is This the End for Joey Votto?” On his Twitter account, he wrote: “Five months left. Enjoy the show.”
He gave no explanation on his tweet.
The Reds are scheduled to hold a Star Wars Joey Votto bobblehead giveaway at Great American Ball Park on Saturday night when they play Pittsburgh.