Blach has lost his spot in the rotation, according to John Shea of the San Francisco Chronicle.
The Giants had been deploying a six-man rotation following Johnny Cueto's return from the disabled list, but with four scheduled off days providing plenty of rest for their starters down the stretch, Blach will be bumped to the bullpen. The 26-year-old has struggled over his last five starts (0-5 with a 7.90 ERA) after providing decent results with his pitch-to-contact style earlier this season. Blach will likely get the first call should a spot reopen in the rotation.