Ag_07 said:
I'll let irish get into more but I think FIP is actually a pretty well respected metric.
It measures a pitcher's performance on only what he has total control over (HRs, Ks, walks, and HBPs). It doesn't take into account balls in play. I think some will even say to look at FIP and not ERA as it's more true.
Yes. FIP is a great metric to do just what you said, when balanced against ERA, it can show regression coming or if a pitcher has "out performed his peripherals."
If I could only know FIP or ERA, I would choose FIP.
The only real wart to FIP is that some pitchers can genuinely be unlucky on homeruns if their HR/FB rate is high. The idea is that FIP measure pitchers control (walks), stuff (strikeouts), and hard contact rate (homers). Sometimes pitcher can be unlucky and give up a ton of fence scraping homers which could skew FIP.
xFIP takes things a bit further to account for this and normalizes HR/FB rate to league average and LOB% to league average which is usually 70%.