He joined the Mets again that September, going 3-for-10 in four games, but was not part of the "Miracle Mets" post season roster. Heise was sent along with Jim Gosger from the Mets to the San Francisco Giants for Ray Sadecki and Dave Marshall on December 12, 1969.
Heise's return to the Mets in September did not secure him a spot on the "Miracle Mets" postseason roster. Nevertheless, he was eventually traded by the Mets to the San Francisco Giants on December 12, 1969, as part of a larger deal involving Ray Sadecki and Dave Marshall.