16. Jhoulys Chacin (Rockies Career WAR 14.7)
Jhoulys Chacin is one of the first on this list I feel should have been much higher had it not been for some bad luck on the field and with the injury bug.
In just 6 seasons in purple, he littered the Rockies record book with his name. He is in the top-5 in all major pitching categories except wins. His natural stuff was absolutely filthy and could go toe-toe with Adam Ottavino for best slider in team history. Despite the 2nd-best career ERA (3.78) in team history, he only won 38 games, which was a result of seriously poor run support and command that would evaporate in the middle of games.
These mixed with late-career injuries sapped him of much of his potential and keeps him out of the top-15. His best year came in 2013 where he pitched to the tune of a 3.47 ERA and 126 K’s in 197.1 IP, throwing in 14 wins for an ERA+ of 129 and 5.8 Pitching WAR (career-high).