Xander Bogaerts, Red Sox
The most exciting player during the Red Sox run to the World Series last year was the only guy who couldn't grow a beard. Luckily he turned 21 just as the playoffs began, so he was able to legally drink champagne after Boston took the title. Bogaerts only has 18 regular season games on his resume, which is why the quick-handed shortstop's .412 on-base percentage in the pressure-filled playoffs was so astonishing. The Red Sox will need consistency like that this season in order to maintain momentum.