Core four, core five, core two, and core three

So, the sports folks talk about the N.Y. Yankees "core four" (Jeter, Posada, Pettitte, Rivera).  How about the "core five"?  Just add Bernie Williams to the group and you have the real core of those great Yankee teams.  In addition, they would never have been as great without all the "other" players  --  you know, the TEAM.  All those guys that rose to the occasion time after time. 

I recently heard some "sports pundit" talking about the S.F. Giants "core" of Baumgarner and Posey.  How about some love for "The Panda"?  How about those three home runs?  How about his clutch hitting and fielding?  Doesn't any of it elevate him to "the core"?