Neil Walker’s official return to PNC Park and Jonathon Niese’s first start against his former team will have to wait another day. The scheduled game between the Mets and Pirates on Monday night at PNC Park was postponed before it could begin due to rain. The two clubs will play a straight doubleheader Tuesday, beginning at 4:05 p.m. ET, with the second game beginning approximately 30 minutes after the conclusion of the first game.