The team did not say why Bruce was placed on the list. He'll be forced to miss a minimum of three games and can miss no more than seven.
Bruce is batting just .215 this season, with 10 home runs and 42 RBI. Since the All-Star break, Bruce has had three hits in 32 at-bats.
Cincinnati called up reliever Curtis Partch to take Bruce's spot on the roster. In 30 appearances for Triple A Louisville this season, Partch has a 5.45 ERA.
The Reds were 52-53 entering Tuesday, and sat 4.5 games behind the second Wild Card spot.
- Dan Gartland