Its no secret that the Cardinals have some power arms in their organization. Its part of the reason that the Cards farm system was rated the best in MLB and also why the Cardinals rotation has been so successful.
But, how do the Cardinals power arms compare to the rest of MLB?
Well, thanks to Fangraphs and Pitch/Fx, we can compare how the Cards pitchers' average fastball velocity compares to others around the majors.
For example, of all pitchers that have pitched at least one inning in the majors, the Cardinals have two pitchers in the top 8 in terms of average velocity, Carlos Martinez at 97.1 mph and Trevor Rosenthal at 96.3 mph. Martinez ranks 4th in average velocity, behind only Bruce Rondon, who has as average velocity of 99.3 mph, but has only pitched 2.1 innings; the "Cuban Missile" Aroldis Chapman, who averages 97.4 mph; and Kevlin Herrera, who averages 97.2 mph.
Looking at those numbers, it easy to understand why the Cardinals want to keep developing Martinez as a starter, as his plus fastball, as well as other potential plus pitchers, give him "ace" upside.
Rosenthal, on the other hand, may be best suited for relief, just like Chapman of the Reds, as he has dominated in that role. I could easily see Rosenthal taking over the closing duties next year, should Edward Mujica leave via free agency.
As for the starters, Shelby Miller leads the Cards with an average velocity of 93.4 mph. However, that is only good enough for 11th place among starting pitchers (identified as those with over 50 innings).
Lance Lynn is the next highest Cardinals starter on the list, checking in at # 31, with an average fastball of 92.1 mph. In his two starts, Michael Wacha has averaged 92.5 mph on his fastball, which would have placed him 21st, tied with Clayton Kershaw, had he pitched enough innings to qualify.
Cardinals ace Adam Wainwright only averages 90.9 mph on his fastball, which places him 62nd on the list. However, he more than makes up for it with his devastating curve.
Finally, I should point out that throwing hard does not always translate to success. Two of the Cardinals hardest throwers, Maikel Cleto (95.2 mph) and Victor Marte (94.3 mph) have struggled at the major league level, as has Mitchell Boggs this year, despite his 93.7 mph fastball.
There's more to pitching than just rearing back and throwing high 90's heat, but, as most teams and scouts will tell you, having a big fastball is probably the number 1 indicator for future success.