With the playoff races shaping up and four of Major League Baseball's six divisions still up for grabs, every team left in contention has an X-Factor that could potentially drive them into October or send them home for an early winter.
Generally speaking, an "X-Factor" is simply a variable posing a great chance at having a significant impact on an outcome. In this case, it could be an individual player, a tendency or even an entire aspect of one team. Every team has at least one of the above—and it could make or break their season.
There are 13 teams still vying for a trip to the playoffs, although some are closer to the fight than others.
Here is every contender's biggest X-factor down the stretch.