A Tale of Two Pitchers
Pitcher A is a 6-1, 195 pound lefthanded pitcher. He has an upper-80s, low-90s fastball, and a big-breaking, nasty curveball. He made his major league debut at midseason at the age of 22, and puts up the following numbers for a horrible team:
3-6 in 12 starts, 3.58 ERA, 43/24 K/BB in 78 innings, 76 hits allowed, ERA+ 111.
The next year, Pitcher A makes 32 starts for a really awful team, though it's a team filled with young players who might get better. He goes
10-14 in 32 starts, 4.32 ERA, 129/80 K/BB in 209 innings, 201 hits allowed, ERA+ 98. Not bad, eh?
The second pitcher is Pitcher B. He is a year younger than Pitcher A, 6-4, 200 pounds. Like pitcher A, he has an upper-80s, low-90s fastball. His curve isn't as good as pitcher A's, but he has an outstanding changeup, at least potentially. In his rookie year (corresponding to Pitcher A's second year), Pitcher B goes
4-10 in 22 starts, 5.21 ERA, 84/38 K/BB in 126 innings, 152 hits allowed, ERA+ 81.
In his second year he is even worse, going
7-15 in 34 starts, 5.49 ERA, 127/92 K/BB in 210 innings, 242 hits allowed, ERA+ 78.
Now, because of the way I am presenting this question, you no doubt expect that Pitcher B, despite his worse numbers, ended up being the better pitcher. And that's true, Pitcher B had an outstanding third year, and eventually turned into a Cy Young winner. Pitcher A, meanwhile, fell apart completely in his third year, ended up back in the minors, and eventually had a small amount of success as a LOOGY.
What happened? Pitcher A had mechanical problems, lost much of the zip on his fastball, lost his command, lost his confidence. He also did the wrong kind of weight training, bulked up too much in an attempt to throw harder. This backfired and he lost flexibility, reducing his velocity, not increasing it. Pitcher B, on the other hand, was able to refine his mechanics, improve his control, and overcame the initial nervousness he showed in his first two seasons.
But just on a statistical basis, looking at the first two seasons of their careers, there was no reason to expect that Pitcher B would have a much better career than Pitcher A. Note that these two pitcher are pitching for the same team at the same time, so they have the same sort of offensive and defensive support.
Who are these guys?