Blach will transition to a bullpen role starting Friday, Alex Pavlovic of NBC Sports Bay Area reports.
With Chris Stratton and Andrew Suarez named as the starters for Friday and Saturday, Blach will be used as a relief pitcher going forward. He made 12 starts for the Giants in 2018, accruing a 4.96 ERA and 1.61 WHIP with 31 strikeouts and 23 walks over 61.2 innings.