The Red Sox would prefer to not have to worry about any tiebreakers. If they win Sunday against the Nationals, they won't have to, as that would lock them into being the home team for the American League Wild Card Game.
If they lose, though, things get complicated. The Red Sox know they will still have at least one more game to play, but they may very well need to win a play-in game just to get to the Wild Card Game depending on what the Yankees, Blue Jays and Mariners do Sunday.
The most chaotic scenario involves a four-way tiebreaker, which would happen if the Red Sox and Yankees both lose Sunday and the Blue Jays and Mariners both win.
In that scenario, the Red Sox and Blue Jays would each host a play-in game on Monday. The Yankees would then get to choose to travel to either Boston or Toronto, with Seattle left to travel to whichever one New York doesn't pick.
According to ESPN's Jeff Passan, the Yankees have already made their choice, and they've chosen to play the Red Sox at Fenway Park rather than the Blue Jays in Toronto.
That certainly adds an interesting wrinkle should things ultimately play out this way, but the Yankees' choice shouldn't really be surprising. The Yankees have been slightly better against the Red Sox overall (9-10 vs. Boston, 8-11 vs. Toronto), and more importantly, they've won each of the last six meetings against the Red Sox, including a three-game sweep at Fenway last weekend.