I think the health of a team going into the playoffs and how they are playing in September may determine success. The Sox have been up and down for about a month. Does Grandal being out affect the pitching? If so then the backup catcher does impact a team. If guys like TA or Abreu are out for postseason, that could have a major impact. Gio or Lynn are really important pieces of our success. Maybe having Kimbrel is now insurance on Hendricks who is also a key component.
But maybe we arrive healthy and opponents have injuries going into playoffs and we get an advantage. So much can happen between now and lat September affecting all the contenders that it is too early to speculate.