Keller and the Pirates won't face the Mets on Monday after the game was postponed due to inclement weather in Pittsburgh, Justice delos Santos of MLB.com reports.
The two teams are set to make up the contest as part of a split doubleheader Wednesday. Because the Pirates have an open date in the schedule Thursday, the team isn't expected to add a temporary seventh starter to the rotation, so Keller should stay on schedule to make a start against the Mets either Tuesday or Wednesday. Bryse Wilson and Johan Oviedo are in line to start the other two contests of the series.