You might as well start with something we can all agree on: No baseball team is perfect, therefore it follows that every baseball team has a weakness. Now, the Indians might have fewer weaknesses than, say, the Padres, and the Indians' weaknesses might only be relative, but every last ballclub has room to improve. Even the clubs that are going to the playoffs.
The concept here is simple. At this writing, there are a dozen teams either headed to the postseason or almost headed to the postseason. I've cut out teams a little too far away, like the Rangers, Mariners and Cardinals -- there's only so much time remaining. We're left with six teams in each league. Five will advance, but all 12 have issues.
For each team, I've identified one key vulnerability. They're not all equal in significance, but some teams have bigger problems than others. Along with the problems, I'm offering potential ways to cover them up moving forward. Only one team from this group will win the World Series, but that team will have probably addressed the weakness identified here. That's the way winning works.
American League
Weakness: Lack of power. Last season, the Red Sox ranked fifth in baseball in isolated power, so they ranked first in runs scored. This season, without David Ortiz, they rank 28th in baseball in isolated power, so they rank 10th in runs scored. They're 27th in home runs, between the Phillies and the Braves, which means the Red Sox need to sequence baserunners together. A difficult prospect against playoff competition.
Patch: There's one thing I like about the Red Sox lineup. As much as it might be relatively punchless, it collectively has baseball's third-lowest strikeout rate. Low-strikeout hitters tend to hold up better against higher-strikeout playoff competition, as few things are more prized in October than bat-to-ball skills. Part of the solution here is just the flipping of the calendar. The Red Sox have also been one of the better baserunning teams. The Sox have five or six players who can effectively steal a base, and, given the chance, they should keep trying to push the envelope.