The Baltimore Orioles placed minor league pitcher Jon Keller on the 7-Day Disabled List Thursday with a left intercostal strain.

The intercostal muscles are in the rib-cage area and are involved with the mechanical aspect of breathing.

Keller, from Cedar Rapids, has a 0-0 record and 8.31 ERA in two games with Frederick in the High-A Carolina League. He had a 3-0 record and 1.59 ERA in 24 games with Delmarva in the Low-A Southern League before being promoted this season.

Keller's last appearance for Frederick was July 25. He pitched two innings and allowed four runs (three earned) on five hits and four walks.