Mahle (hamstring) had been scheduled to make a rehab start with Triple-A Sacramento on Sunday before the game was postponed due to heavy rain in Sugar Land.
Mahle has been on the shelf for about two and a half weeks due to a left hamstring strain, so he's unlikely to require an extended minor-league assignment before being deemed ready to return from the 15-day injured list. As a result of Sunday's postponement, it's unclear whether the Giants still intend to have Mahle make a rehab start for an affiliate over the next day or two, or if he'll instead opt to throw a simulated game. Mahle had posted a 6.04 ERA, 1.54 WHIP and 57:24 K:BB in 56.2 innings over 11 starts with the Giants prior to landing on the IL.