Bielak was optioned to the alternate training site Sunday, Jake Kaplan of The Athletic reports.
Bielak surrendered four runs over two innings Saturday, so he'll head to the alternate site in favor of a fresh bullpen arm. He has a 6.75 ERA, 1.75 WHIP and 26:17 K:BB across 32 innings this season. Nivaldo Rodriguez was recalled in a corresponding move.