Here's why at least to me.
http://www.espn.com/mlb/team/schedule/_/name/bos/boston-red-sox
Sale is lined up for the last day with 4 days rest, just say Astros are fighting for best record, and Sox and Yanks are tied (or game behind), on last day, they go with Sale, and we lose, wont have him for Wildcard or Play-off.
Just throwing scenarios out there, next time a runner is thrown out on stupid base running play and might cost you a run, and a game. That's how close baseball is, now.
You absolutely play for the moment, but if that moment is stupid, could cost you for the future.