The move is retroactive to Thursday, reports Kent Taylor of WAVE-TV.
Votto told Mark Sheldon of MLB.com that he suffered the injury on the final swing of batting practice before Thursday's game, which led to the team scratching him from the lineup that day. He hasn't participated in any baseball activities since.
"I haven't swung a bat yet. So, I haven't done much throwing or running yet," Votto said.
The injury adds another chapter to what's been the 35-year-old former MVP's worst year as a major-leaguer. Votto, who's won seven on-base percentage titles in 13 seasons, is slashing just .262/.352/.410 with 12 homers, 39 RBIs, 60 runs scored, and 57 walks to 100 strikeouts. He's been hot of late, though, as he owns a .864 OPS in August and was in the midst of a six-game hit streak at the time of his injury.
Infielder Brian O'Grady was recalled from Triple-A Louisville in a corresponding move.