Pablo López should be pitching much better than he has been this season. While he has a 5.25 ERA, he has an expected ERA (xERA) of 3.25, according to Baseball Savant. The low xERA is a product of López’s strikeout ability, low walk rate, and usually suppressed contact quality. Nevertheless, López has had a few tough outings in a row. So why should we care about his expected performance?
Even as López struggles to command his secondaries and as his four-seamer coaxes fewer whiffs, he’s supposed to be great. A 5.25 ERA is nothing to celebrate. However, if López’s floor looks like a 27.9-4.0 K-BB%, Minnesota may have a future Cy Young winner in its rotation.
It’d make more sense to declare something of that magnitude if López was sporting a 2.60 ERA and 32.4-5.8 K-BB% like old friend Sonny Gray. However, López is counterintuitively showcasing his potential amidst one of the worst stretches of his career.
It’s rare for pitchers, even bona fide aces, to have command of every pitch in their arsenal. However, López has seen the Command+ of his pitches (per MLBPitchProfiler) dip almost across the board, even if they’re seemingly minor regresses. Command+ attempts to quantify how well a pitcher commands his pitches. López’s changeup command has lowered from 107 to 104, his curveball from 101 to 96, and his four-seamer from 105 to 102.
López’s shadow percentage highlights his poorer command, meaning fewer of these pitches are finding the edges of the zone.
Even if López’s command is solid, he isn’t pitching like it. He’s filling the zone with more four-seamers than in past seasons, resulting in worse contact allowed (meaning better for the hitters). López is throwing more four-seamers and locating them in the zone more often.
López has the most success with his four-seamer when he locates it high in the zone. However, given abnormally unreliable secondaries, he has needed to fill the entire zone. There’s a compound effect. When López throws one of his secondary offerings, he’s throwing it to a hitter who is more keen on swinging.
That seemed to happen against the Washington Nationals on May 20 to Luis García Jr.
After missing with a four-seamer up and away, López throws Garcia a sweeper that starts on the outside of the zone. Had he thrown his changeup, sinker, or curveball, the pitch would’ve fallen outside for a ball. Knowing López has been throwing more four-seamers recently, he’s ready to swing and stays in on the sweeper well enough to smack it 378 feet:
Some pitchers have such incredible four-seamers that they can fill up the zone and still avoid contact. López has a respectable four-seamer shape, but it’s flatter and faster than many across the league. Still, it may not be good enough to carry him against quality lineups.
López’s increased zone rate on his four-seamer is likely intentional. However, the increase in zone rate for his sinker probably isn’t.
Usually an effective jammer, López’s sinker may be his worst-performing pitch this season. Hitters have hit a line drive on 33% of balls in play against López’s sinker. The 38.9% flare/burners and 11.1% barrels against the pitch are just as concerning.
López is still attempting to use it to jam right-handers, and he’s still managing to locate the pitch inside. However, he’s leaving it over the plate too often, as you can see below:
Considering how often he’s locating his four-seamer in the zone, the sinker could become a dominant pitch for him. A hitter may be unable to identify a sinker about to run in on his hands. However, López isn’t punishing them for swinging at sinkers like he did in the past.
While López hasn’t been at his best, his peripheral stats indicate he’s pitching as well as he did last year.
K-BB% has been around forever, and for good reason. It’s one of the best indicators of future ERA, as is FIP. López happens to have a 3.88 FIP, which is much lower than his 5.25 ERA. With a stellar 27.9-4.0 K-BB% (23.9) that’s almost exactly the same as the 29.2-6.0 (23.2) mark he posted last year, López is still performing well despite worse command.
López hasn’t lost any ability. He’s still supposed to be a great pitcher. The results haven’t materialized, but López is subject to the same laws of nature that every other poor ERA-good K-BB% pitcher has experienced before him.
