The MLB playoffs begin today, kicking off a new 12-team format that begins with four best-of-three wild-card series played entirely at the home of the higher seed — No. 6 Rays at No. 3 Guardians, No. 6 Phillies at No. 3 Cardinals, No. 5 Mariners at No. 4 Blue Jays and No. 5 Padres at No. 4 Mets — with no days off between games. Best-of-five Division Series will follow — with no re-seeding — featuring the top two seeds in each league (Dodgers, Braves, Astros, Yankees), who receive first-round byes.

Here are the top storylines to watch in this unique postseason:

The value of the bye

The new playoff format has given regular-season success its greatest importance since the first version of the wild card was introduced in 1995, rewarding top-two seeds with five days off and the opportunity to set their rotations while wild-card teams likely use their aces to try to advance, before entering the Division Series at a disadvantage. When the one-game wild-card format was in place from 2012-2021 — it was not used during the truncated 2020 season — only two teams (2014 Giants, 2019 Nationals) won the World Series after playing in the opening round.