The Orioles designated Pennington for assignment Wednesday, Jake Rill of MLB.com reports.

EDGE Analysis

Pennington has made two appearances in the minors this season, during which he's given up five earned runs in one combined inning between High-A Aberdeen and Triple-A Norfolk. While he continues to work on his mechanics in the minors, he'll give up his spot on the Orioles' 40-man roster for Luis F. Castillo, who was acquired from the Mariners on Wednesday.