If the Sox and Yanks wind up tied—and somewhere, you can bet Rob Manfred is praying for this—they would play a one-game tiebreaker in the Bronx to determine the division champion, with the loser most likely winding up as the host of the wild card game.
https://www.si.com/mlb/2017/09/22/american-league-playoff-race-team-entropy?utm_campaign=si-mlb&utm_source=twitter.com&utm_medium=social&xid=socialflow_twitter_si