Blue Jays-Orioles
Never has one rivalry hinged so much on the free-agent fate of a 33-year-old reliever. Depending on where Darren O'Day signs this winter, the Blue Jays could have a new foe, a renewed one, or, oddly enough, they might employ one. O'Day and Blue Jays star Jose Bautista are at the center of this rivalry, though it also includes the likes of Marcus Stroman, Delmon Young, and even mild-mannered Adam Jones. Blue Jays manager John Gibbons described the bitter hatred best: "Not everybody likes each other, necessarily."