Gregory John Kosc (wuxuu dhashay 27 Abriil 1949) waa garsoore hore oo ka tirsan Major League Baseball oo ka soo shaqeeyay Horyaalka Mareykanka laga bilaabo 1976 ilaa 1999. Wuxuu garsoore ka ahaa Taxanaha Adduunka 1987 iyo 1997, iyo Ciyaarta Xiddigaha oo dhan 1981 iyo 1992. Wuxuu sidoo kale ka shaqeeyay Horyaalka American League ee 1979, 1988 iyo 1993
, iyo Horyaalka American League ee 1996 iyo 1997. Kosc wuxuu xirtay dharka lambarka 18 markii garsoorayaasha horyaalka American League ay qaateen 1980.