Or, at least a sizable fraction of the sequencing thing he did in 2024?
This would be a pretty good article if I or anyone would get around to it, but instead… I’m outsourcing. And crowdsourcing.
Reynaldo Lopez had a 48/74/85 line in 2024 (ERA-/FIP-/xFIP-). His xERA was 0.50 higher than his xFIP, his SIERA was also higher than his xFIP. The extreme disparity between his ERA estimators and ERA itself, as well as between some of the ERA estimators themselves, was pretty comical: did you know that he was the first guy since Justin Verlander in 2022 to have a sub-2.00 ERA season in 135+ innings (Paul Skenes only had 133 innings last year). He was the first Brave to do so in 135+ innings since Kris Medlen back in 2012.
If we expand the field to the 157 pitchers with the most innings, Lopez had by far the biggest xERA-ERA (basically xwOBA-wOBA) gap, with hish 3.94 xERA nearly 2.00 higher than his 1.99 ERA; there was only one other pitcher above 1.50, and only ten others with a gap above 1.00. (Of course, on the flip side, Reid Detmers had a 2.56 gap the other way, but in general we’re talking just 19 of 157 pitchers, or about 1-in-8, having a gap of 1.00 in either direction, and Lopez’ was double that minimum threshold.) He also had a top-ten FIP-ERA gap, and the fourth-biggest xFIP-ERA gap (in terms of outperforming the peripherals, not absolute value).
A lot of times, when this sort of thing happens across a variety of ERA estimators, there are multiple reasons — weird stuff, sequencing, ball-in-play stuff, and HR/FB stuff. But for Lopez, though, it’s really all about sequencing. Among that same set of 157 pitchers, no one had more of their ERA-FIP gap attributable to sequencing (though Logan Gilbert and Dylan Cease were as screwed by sequencing, or more, as Lopez benefited from it).
The question is: why? And, is the “why” a reason for Lopez to be able to repeat it in 2025? Note that, “I dunno, one guy getting really fortunate with sequencing isn’t that weird and it won’t happen to him again in 2025” is a perfectly legitimate answer.
That said, I do think a deeper dive is interesting for anyone that wants to take the plunge. Lopez’ by-base-out-state splits are interesting, showing him basically pitching around guys in higher-leverage spots with the idea that they’ll either chase a slider or walk so he can try to get the next guy to do the same, and amping up his velocity to try to end potentially-squidgy innings as well. Of the 34 times he exceeded 98 mph in 2024, 26 of them (over three-fourths) came with two outs.
While xwOBA for pitchers is not really predictive for various reasons, it’s also worth nothing that Lopez had a .320s xwOBA-against with no one on, but that it dropped to .290 with RISP — heavily counterbalancing the extra hit to xwOBA he took from walking a bunch of guys with RISP. Sure, a lot of the sequencing could be explained by the fact that he had a .177 wOBA-against on a .290 xwOBA-against with RISP, but it’s still interesting because, for the league, wOBA and xwOBA increase with RISP (because the set of RISP situations overrepresents poorer pitchers). So yeah, there’s some stuff to work with here. Or, you can just give your off the cuff thoughts.