Byrdak was placed on the 15-day disabled list with soreness in his left shoulder on August 3.
Byrdak leads the league in relief appearances with 56, during which he is 2-2 with a 4.40 ERA in 30 2/3 innings.
He has given up 18 hits. 18 walks and 34 strikeouts while giving up 15 earned runs.
This is the same injury that sidelined both Johan Santana and Chris Young, both of whom needed more than a year to fully recover surgery.