Posted by pjfoster13 on 7/23/2015 1:32:00 PM (view original):
Posted by a_ersberg on 7/22/2015 9:13:00 PM (view original):
16 gf/fb, he's a HR machine anyways ;)
gb/fb defines ground ball outs rather than ground ball events. I think of gb/fb like a double-play rating. low gb/fb pitchers technically face more batters because they have to get the outs one at a time, and will theoretically give up a higher volume of HR, but it's not because of gb/fb itself ...
there are plenty of examples of 95+ gb/fb who have league average HR rates and other examples of 16 gb/fb who have above-average HR rates. Hr rate relates more to command (pitches + control) and splits, and year-over-year variance relates to the fluctuations in the quality of batters the pitcher faces.
What are you basing that on other than some examples of pitchers who don't fit the theory? Numbers back up that HR are directly affected by GB/FB. Looking at the three worlds I'm in, the most HR-prone pitchers consistently have lower GB/FB than less HR-prone pitchers. I only looked at the 25 P who allowed the most HR in each world since that was a quick way to get a snapshot:
Pete Rose
1-10 most HR allowed: 60.7 avg GB/FB rating
16-25: 73.1
20% higher average GBFB rating for 16-25 than 1-10 in most HR allowed
Rickey
1-10: 50.4
16-25: 66.1
31% difference
Sweet Lou
1-10: 54.4
16-25: 70.3
29% difference
That's a huge difference in HR allowed for low-GB vs. high-GB. To look at it another way and eliminate defense and park factor, I looked at my staff in Rickey. Of 13 pitchers on my ML staff, the three best GB/FB ratios were 2-4-9 in HR allowed. The three worst GB/FB were 10-13-12. I only have two P with low (below 50) GB/FB; they are the worst on my team at giving up HR/inning by a huge margin over the other 11.
Of course other ratings matter, but GB/FB drives HR allowed the way Eye drives OBP for hitters. You can find examples of almost anything in baseball. Ozzie Smith hitting a walkoff HR in a WS game does not mean Ozzie Smith is a HR hitter. Benjie Molina getting a bounce for a cycle-finishing triple does not make Molina a good bet for triples. A 16 GB/FB with phenomenal splits/control/velocity might give up fewer HR than average, and a 95 GB/FB who otherwise stinks and gets hit all over the park might give up higher-than-average HR because he allows so many balls in play. But all else being equal, a 16 GB/FB is going to give up a whole lot more HR than a 95 GB/FB; or even a 40 GB/FB.