John Lackey can become the first pitcher ever to start and win the clinching game of a World Series for two different teams. He won Game 7 of the 2002 World Series for Anaheim as a 24-year-old. That was 4,021 days ago.
Jimmy Key (1992 with Toronto in relief, 1996 with the Yankees as starter) and Catfish Hunter (1972 with Oakland in relief, 1978 with the Yankees as starter) are the only other pitchers to earn a Series-clinching win with two teams.
There have been 10 pitchers overall who have clinched two World Series, including these six who did it as a starter both times: Bob Gibson, Lefty Gomez, Sandy Koufax, Art Nehf, Andy Pettitte, and Vic Raschi.