Posted by MikeT23 on 5/19/2017 1:04:00 PM (view original):
I have no intention of arguing with you, mostly because I KNOW I can't find the pitchers I tested over several seasons, but it is because of the attribute. Much like PC, the difference between 20 and 30 is insignificant but 0/30 is noticeable. That said, I will concede two things:
1. My test was a tiny sample size. It included three pitchers(0, 50ish, 90+) with otherwise similar ratings over 300+ innings each.
2. I did not take into account BF or DP. But I can't imagine that 0 faced a hundred more batters than 90+ as their WHIPs were similar while their ERA was not.
It's not because of the attribute, it's just not.
In my first example, the players were almost identical:
Pitcher A (RHP) has splits of 65vL and 75vR, with average pitch of 70, and with GBFB of 99
Pitcher B (RHP) also has splits of 65vL and 75vR, also average pitch of 70, but GBFB of 0
But consider a different example where
Pitcher A (RHP) has splits of 65vL and 75vR, with average pitch of 60, and with GBFB of 99
Pitcher B (RHP) also has splits of 75vL and 85vR, also average pitch of 70, but GBFB of 0
Pitcher A will give up WAY more home runs, both rate and volume, because he's nowhere near as good. GBFB has absolutely nothing whatsoever to do with causation. VEL and GBFB are simply contributing factors towards ERA, they skew ERA-relative-to-WHIP in one direction or another. Slugging correlates most directly with average-pitch
"2. I did not take into account BF or DP. But I can't imagine that 0 faced a hundred more batters than 90+ as their WHIPs were similar while their ERA was not."
The 0 GBFB gives up more runs because of baserunning. Let's say for example your SP leads off the 6th inning with three consecutive walks.
-Player A (GBFB of 99) inherits three runners and has a certain runs-expectancy that can be mathematically defined. His ability to heavily-skew groundballs severely limits the offense's opportunity to score and helps his own ERA, the previous pitcher's ERA, and the team's ERA as a whole.
-Player B (all other attributes equal except for GBFB of 0) will give up a disproportionately-high volume of "productive outs" aka sac flies, etc and therefore drastically under-performs for the previous pitcher's ERA and the team's ERA.
This is similarly-observed when each player starts the inning and doesn't get pulled, player A can get himself out of those jams while player B does not. This is how Baserunning contributes to ERA.