Reynaldo Lopez was the best pitcher that Sox had this season, no ifs, ands or buts about it. His velocity ticked up over one mph on his fastball compared to 2017, and he added an above-average slider. That slider was rated 34th in baseball among hurlers with at least 120 innings pitched, so considering this was the first season López ever threw a slider, that’s a great feat.
However, Lopez did not add a slider as just another devastating tool in his arsenal. The truth is, he needed to add a slider, because his curveball and fastball faltered mightily for most of the season.
Every scouting report on Lopez has the fastball and curve as by far his best pitches. His fastball ranged from great to elite, and the curveball was above-average to great. When they are on, they are great pitches.
However, for most of the year, the fastball was a negative pitch, and the curve was much worse than normal. In 2018, hitters had a 123 wRC+ against Lopez’s fastball, even with the uptick in velocity. The curveball was much worse, with a 226 wRC+. That seems to be a major reason why López’s curveball usage fell from 12.8% in 2017 to 5.5%. Just to round out pitches used, López’s changeup was at 112 wRC+ against, slightly better than last year. Meanwhile, his slider proved dominant, as Lopez only allowed a 39 wRC+. Sliders like you see in the video below are why the pitch was so effective.
Sweet slider to freeze Justin Smoak by Reynaldo Lopez to cap off a great outing - 6.0 IP, 1 ER, 2 Hits, 2 BBs, 6 Ks. pic.twitter.com/BZlQW9JjTD— Pitcher List (@PitcherList) April 3, 2018
But for the season, López was really not overly impressive, because of how up-and-down his best stuff was. His 18.9 K%, though it was an improvement from last season, was ranked 91st out of 116 pitchers with a minimum 120 innings pitched. Meanwhile, his 9.4 BB% was 21st-worst rate among pitchers. Just to really hammer home how bad López was for the season, he had the fourth-worst xFIP (right behind Lucas Giolito and Carlos Rodón), along with the 22nd-worst FIP. Obviously, only having one positively-rated pitch in terms of wRC+ didn’t help.
But pitch effectiveness is really only part of the story.
Batters crushed Lopez. His 47.1% fly ball rate was extremely high for the type of contact he was giving up. His hard-hit percentage saw an 8% increase (to 35.3%) in 2018. Hard contact, according to Baseball Savant, are hits clocked at 95 mph or more. López gave up 199 batted balls that were 95 mph or faster, 13th-most in baseball.
The hard contact led to an astronomical expected weighted on-base average on contact (wWOBACON) of .370. To put that into perspective, Joey Votto had the 19th-best wOBA in MLB at .370. So, whenever Lopez gave up contact, on average, that batter was 2018 Joey Votto. That is not good.
Even if you ignore the hard contact, López’s expected wOBA was .334, which ranks 223rd of 274. So whenever a batter went up against Lopez, the result basically would have been 2018 Jose Abreu, who had a wOBA of .337.
That includes even the last two months of the season, when López had changeups like this:
Reynaldo Lopez makes Brett Gardner look foolish with this 86 mph drifting Changeup. pic.twitter.com/UqgdFp2Uyu— Pitcher List (@PitcherList) August 30, 2018
During his hot stretch to end 2018, López was better, but not where he should be. In 11 starts in August and September, López had a 2.70 ERA, 3.42 FIP, and 4.33 xFIP. That’s a nice improvement, but his base stats still did not translate as well as you’d expect. The strikeouts did improve, but for a pitcher with stuff like López’s, an 8.78 K/9 is low (though the walks were at a respectable 2.70 BB/9). Also, if you take a look at how López’s pitches rated in the last third of the season, they all improved.
However, that does not paint a full picture.
There were two starts where López did not even use his curveball. In the other nine starts, there were five games where his curve had a negative impact, and four times where it was positive. His changeup improved overall, but it was either his best pitch of the day, or (in four of 11 starts) it was beyond terrible. López had two starts where his change was rated at or worse than -10.0, which is have-you-ever-thrown-a-changeup-in-your-life? bad.
Even the slider, López’s best pitch in 2018, faltered several times down the stretch. The fastball was the only pitch that showed real improvement and consistency. That is probably why Reynaldo used his fastball 60.5% of the time, which is too much use of any one pitch. But he needed to overuse his heat, because it seems he could not totally trust any other offering.
Now, 2018 was not really a good year for Reynaldo Lopez, but that does not mean he has lost any prospect hype. After all, without any consistency from his pitches, he still ended up with a 3.91 ERA in 188 innings.
López’s fastball usage needs to drop closer to the 50% mark, which would also help him with his first-inning woes. In 2018, the first inning was by far López’s worst inning, with a 5.91 ERA — coincidentally, the first time through the order is when he uses his fastball the most.
Because his curveball is so highly-rated by scouts, López still has a chance to find it. A 95 mph fastball with a proven, albeit inconsistent slider, and a changeup that is masterful when López has a feel for it would be a devastating four-pitch arsenal — if he can recoup his curve.
At the very least, in 2018 López proved he can be a workhorse, and have an above-average ERA without good pitches. But this offseason will be huge for the young starter if he wants to become a starting pitcher, instead of a reliever pretending to start.
For now, from a pure stuff standpoint, there is no reason to favor López over Giolito in the future.