Any of the AL division leaders have a shot at winning the pennant. All have strong starting pitching with Cy Young level aces (Kluber, Sale, Keuchel), strong closers (Kimbrel, Giles, Allen). Indians do have the bullpen edge with Andrew Miller and Shaw, but Miller isn't invulnerable, as we saw in the WBC and last year's World Series. Red Sox Achilles is their lack or power, but they try to compensate that with pressuring on the basepads. Their below league average OPS+ is concerning though. Indians beat them on paper, but it's baseball where the choke factor matters more than anything else.
I feel a little less concerned about Red Sox inability to hit the ball hard in the playoffs.

I think most teams step up big time and make it a game of will in GO time. Honestly I'm more worried about Red Sox ability to choke at will during these winding times going INTO the playoffs.

Yankees can still nip them.