Lefthanded starting pitcher: Danny Duffy, Kansas City Royals
Speaking of prospects who have taken forever to break through due to injuries and ineffectiveness, Duffy—who made Baseball America's Top 100 in 2011—helped the Royals to the World Series in 2014 and '15 but didn't qualify for an ERA title until last year, his age-27 season. Appearing in 42 games and making 26 starts, Duffy threw 179 2/3 innings with a 3.51 ERA (124 ERA+, also his average over the past three seasons) and 9.4 K/9. For the past three seasons, he's totaled 9.2 WAR, including a career-best 4.2 in 2016.