NEW YORK -- With thunderstorms scattered throughout the tri-state area on Monday, the Mets postponed their series opener against the Cardinals. The game will be made up as part of a single-admission doubleheader beginning at 3:10 p.m. ET on Tuesday.

Although the doubleheader won’t allow the Mets to alter their pitching plans in a meaningful way, it will allow them to call up an extra pitcher on Tuesday to provide bulk innings for one of the games. The team tentatively plans to start Trevor Williams in Game 1 of the doubleheader, and Taijuan Walker in Game 2. Williams is only stretched out enough to throw around 65 pitches, making the 27th man a significant addition. The Mets will have that pitcher available to them for both games.

Tylor Megill was originally scheduled to start Monday’s series opener against the Cardinals, but he went on the injured list over the weekend due to right biceps tendinitis. The Mets can eventually call up lefty David Peterson to replace him in the rotation, but Peterson won’t be fully rested until Wednesday. (He would slot into the rotation no earlier than Saturday in Denver.) In the interim, Williams will play an important role.

The doubleheader is the Mets’ fourth of the season. Game 2 will begin approximately 30-40 minutes after the conclusion of Game 1.

Fans with tickets for Monday’s originally scheduled game may not use them for admission to Tuesday’s doubleheader. They will instead receive a voucher redeemable for another Mets home game, excluding July 9 (Keith Hernandez’s number retirement), July 26-27 (Subway Series) and Aug. 27 (Old-Timers’ Day).

Fans with tickets for Tuesday’s originally scheduled game can use them for the entire doubleheader.