The left-hander was placed on the 15-day disabled list retroactive to May 24 with an inflamed left elbow after Friday's game.
Gorzelanny said the injury was "like a shin splint in my elbow." He first noticed it playing catch this week.
Balester is 0-0 with an 8.10 ERA in three appearances for the Nationals last month. He's expected to be with the team only for Saturday.
The Nationals will need a starter to replace Gorzelanny on Sunday and could recall right-hander Yunesky Maya from Syracuse.