Harvey was previously only expected to pitch once this series, but this could change if the Mets need to go to the bullpen tomorrow. Collins also said that Noah Syndergaard would be available, as well. As of right now, it sounds like just about everyone will be available for the Mets with the season on the line.
Harvey has never made a relief appearance in the major or minor leagues. In fact, the last time Harvey pitched in relief at any level was during his sophomore year at UNC in 2009. Yesterday we learned that Harvey would be able to make multiple starts in the NLCS should the Mets advance, so it appears that most restraints on Harvey are now off.
In 29 starts this regular season, Harvey was 13-8 with a 2.71 ERA and a 3.05 FIP. He allowed two earned runs in five innings during Monday's Game 3 win.