Here's a look at all tiebreaker scenarios heading into the final day, when for the first time, every game with playoff implications will begin at 3 p.m. ET on Sunday.
• Complete tiebreaker rules
Scenario: Two teams tie for the second Wild Card spot
We'll start with the most likely scenario that would involve an extra game.
If the Astros and Angels tied for the second Wild Card spot, they'd have to play each other on Monday for the right to advance to the AL Wild Card Game presented by Budweiser. Home-field advantage would go to the team with the better head-to-head record, which in this case is the Astros.
Scenario: Two teams tie for best record in the league or for the Wild Card
Unlike the scenario above, these would not involve any extra games.
If the Royals and Blue Jays, for example, finish tied for the best record in the AL, the team with the better head-to-head record (in this case the Blue Jays, who went 4-3 against the Royals) would get home-field advantage throughout the playoffs, including the World Series (thanks to the AL's win in the All-Star Game).
As for the Wild Card, if the Cubs and Pirates -- the NL's two Wild Card clubs -- finish with identical records, they would not play an extra game to determine who gets home-field advantage in the NL Wild Card Game presented by Budweiser. It would go to Chicago by virtue of its 11-8 record against Pittsburgh.
If the Astros win the second AL Wild Card spot and finish tied with the Yankees, the game would be played at Minute Maid Park, as the Astros won the season series, 4-3.
Scenario: Two teams tie for a division title
If the Rangers and Astros finish the season in a tie atop the AL West, they would play a one-game tiebreaker on Monday in Arlington, as Texas won the season series against the Astros. The winner of this game would advance to the AL Division Series, while the loser would head to the AL Wild Card Game against the Yankees.
As noted above, the Astros hold the tiebreaker over the Yankees for home-field advantage in the Wild Card Game, while the Rangers also hold the tiebreaker over New York, having won the season series, 5-2.
Note: Even though a Monday tiebreaker game counts as a regular-season game for statistical purposes, it does not affect the standings as far as tiebreakers go. So, for example, if the Rangers, Astros and Yankees all finish 87-75, and the Rangers and Astros had to play a tiebreaker game on Monday for the AL West title, the loser of that game would still host the Wild Card Game by virtue of a head-to-head record against the Yankees, even though their record in the standings would be 87-76, seemingly a half-game behind New York.