What if the MLB season was a one-and-done tournament, like the NCAA tournament or the FA Cup? The bracket above represents one such scenario based on games actually played to date.
First-round games were based on Opening Day matchups, with teams bracketed by league and roughly by division. Later rounds were decided by the first game after pairings were set. The bracket shows the randomness of baseball (the struggling Red Sox in the semifinals; Atlanta and Philadelphia in the third round), but also strong seasons from the likes of the Royals and Astros.
Based on the remaining schedules, both finalists will be determined by August. The only championship game that could feasibly happen this season, however, is Houston-San Francisco — unless a different pair of finalists happens to meet in the World Series.