Ours Should be 11

Eleven pitchers, that is.

No need to carry more. In fact, any more will make this a lesser Yankees team.

Big Sap (he's been promoted again)
Tiger Tanaka
Sevvy
Happ (a little less hapless—when he can pitch at all)
CC (apparently required by law)

The Big Five in the Pen:
Green
Ottavino
Kahnle
Britton
Chapman

And then, The Remainder:

I would like to see if Mike King or Monty has enough to steal this spot, but although the Yanks have added both to their late-season rosters, they don't seem to have done it for any purpose, such as pitching them.  (Perhaps they are assigned to fetch late-game Klondike Bar snacks from the clubhouse.)

The Remainder is thus most likely to be Luis Cessa, which is, as the song goes, making the best of a bad situation.  Fine.  Cessa can be Mr. Mop-up, and should be pitched in that role until his arm falls off, although it will be difficult to tell when that happens.  CC can join him.

Considering how many off-days there are and how well-rested the Big Five are (a tip of the hat to Ma on that one), there is really no reason to go with any more hurlers.  Again:  any more will just hurt us.

Which should leave:

C—Lettuce, Higgy (with any luck, Sancho is done for the year)

INF—EE, The General, El Conquistador (The Gleyber), Didi (he will surprise us), Gio, Tyler Wade (the hot hand)—and yes, Luke! (or Ford, or Thairo)

OF—Judge, Gardy, Maybin, Stanton, The Red Menace (no avoiding it!)

Any fewer regulars, and we're shorthanded.  With the 14 above, we have a good, deep bench, adjustable for any situation.

Chances are, we're getting outpitched in any case, by any possible opponent save for Minnesota.  Nothing we can do about that now (looking at you, Brian Cashman).  Hence, we're best off carrying the most adjustable, flexible, and deep team we can.