The Royals won their fourth-straight game, winning 6-5 in San Diego against the Padres. The win has improved the Royals’ record to 38-38, and they are now tied for second in the AL Central, as of Saturday morning.
The hitting led Kansas City in their win over San Diego, a common theme during this road trip.
Bobby Witt Jr. hit his 10th home run of the year, and even though he only had one hit, all four of his batted balls were labeled as “hard hits”. Maikel Garcia has another three-hit day, bringing his average up to .319 and OPS to .873 (he needs to be an All-Star). Lastly, Jonathan India had three hits, including a big three-run home run that gave them a 4-0 lead.
Unfortunately, the game ended up being closer than expected due to Lucas Erceg struggling.
Taking the mound with a 4-2 lead in the seventh, the 30-year-old righty gave up two runs on three hits and one walk. He didn’t strike out a single batter, and his strike metrics were pretty underwhelming as well.
Over 29 pitches, Erceg only posted a 44.8% zone rate and 24% CSW. When reviewing his TJ Stats summary from yesterday’s game, the xwOBACON wasn’t bad at .278, but the whiff and chase numbers were subpar.
Against the Padres, he only generated a 25% chase rate and 15.4% whiff rate. San Diego hitters locked in on Erceg, even though his overall stuff profiled well on Friday night (102 overall TJ Stuff+).
His command was erratic on Friday, and that was putting it lightly. He particularly struggled to control his slider, as he only generated one strike with the pitch (a swinging one). He also made some mistakes with the sinker, and his changeup sat too high to be effective, especially against a Padres lineup that is one of the better ones in baseball.
Here’s a look at his pitch type and description charts from Friday via Savant.
Erceg spiked four balls in the dirt and only generated one whiff outside the zone. He had a better command of the four-seamer, locating the ball up and on the edges. Unsurprisingly, his four-seamer had the best zone rate (80%) and second-best whiff rate (50%).
Thankfully, the Royals bailed Erceg out. Not only did he not suffer the loss, but he ended up with the win thanks to Steven Cruz and Carlos Estevez closing the door in the 8th and 9th innings, respectively (though Estevez made it nerve-wracking after giving up a leadoff home run to Manny Machado).
Nonetheless, that’s been two straight mediocre outings for Erceg since coming off the IL. That begs Royals fans to ask the questions: Is something wrong with Erceg in 2025? Or is this just him getting ramped back up after spending so much time on the shelf?
Let’s examine what Erceg has done this year, both before and after his IL stint, and whether or not Royals fans should be concerned about his outlook for the remainder of the season.
Comparing Erceg Pre and Post-Injury
There’s no question that Erceg made a huge impact when he came over from the Athletics at the Trade Deadline last season.
In 23 outings and 25 IP, Erceg posted a 2.88 ERA and 0.84 WHP with 11 saves. He struck out 21 batters and only allowed three walks, making him a dependable option in high-leverage situations in the late innings.
This season, the numbers have been pretty much the same for Erceg, especially pre-injury.
In 28 outings and 27.1 IP, he is sporting a 2.30 ERA and 0.99 WHIP. He has only one save, but he has 14 holds, which ties him for 10th in Major League Baseball, according to Fangraphs.
That said, there have been some red flags, especially in terms of his strike-generating ability.
After posting a 28.5% strikeout rate with the A’s and Royals last year, his rate is down to 19%. His CSW has also gone from 31.3% in 2024 to 25.9% this season, and his swinging strike rate of 11.8% is also a two percent decline from a year ago. On a positive note, he is walking fewer batters at 4.8% (1.5% lower than his rate in 2024). That said, for a pitcher who comes in high-leverage spots, the strikeout decline is concerning.
When examining his TJ Stats metrics this season up to May 24th (his last outing before he went on the IL), it appears that his ability to induce soft contact is the issue, based on his TJ Stuff+ and xwOBACON numbers. Instead, it’s the inconsistency in his chase and whiff rates.
As Royals fans can see, there’s a lot more good than concerning with Erceg’s summary. The 103 TJ Stuff+ is solid (all four pitches have grades over 50, which is good). His zone and chase rates are all above average, and his xwOBACON is around average at .358.
A closer examination, however, reveals some flaws that might have been overlooked if one had only considered the overall numbers.
So much of Erceg’s positive metrics in the first half have been carried by his excellent sinker.
Before his injury, it had a zone rate of 63.7%, a 51.5% chase rate, and a .295 xwOBACON. Those are the best marks in those categories and by a significant margin. In fact, in terms of chase, his sinker was the only pitch with an above-average chase (thus showing that the overall 30.5% rate was primarily due to the sinker’s prowess).
Now, let’s look at what Erceg has done since coming off the IL.
The results haven’t been good, even with a small sample size.
Over this 4.1-inning sample, his WHIP is 2.31, his ERA is 4.15, his FIP is 3.54, and his K-BB% is 0.0. Before his IL stint, his WHIP was 0.74, his ERA was 1.96, and his K-BB% was 17.9%. The only category that’s similar is his FIP, which was 3.42.
Hence, it’s possible that Erceg isn’t as bad as his current stretch suggests. Conversely, it’s also likely that he was out-performing his ERA before his IL stint, based on his much higher FIP.
Two things stick out with Erceg on his TJ Stats summary from this 4.1-inning sample:
1.) His stuff has declined a bit.
2.) He’s not finding the strike zone nearly as much as he did pre-IL.
In terms of the former point, that stuff regression was to be expected after a lower-back injury. Not only is his overall TJ Stuff+ of 101 a two-point decline pre-IL, but his four-seamer and sinker have declined four and five points, respectively. The most significant decline in TJ Stuff+ has been his changeup, which has gone from 107 pre-IL to 100.
Here’s a look at his changeup difference from both before (against Joshua Palacios) and after (against Corey Seager) his IL stint.
In terms of point two, Erceg has struggled immensely with his control, as his zone rate since coming off the IL is 46.6%, a 4.6% decline from his zone rate before the injury. Interestingly enough, his zone rates have been reasonable with his changeup (50%), sinker (70%), and four-seamer (73.3%). Instead, his slider zone rate has been awful at 18.2%.
In terms of the slider heatmap, look how different his pre-IL slider heatmap is from his post-IL one.
Pre-IL, Erceg was either able to do that lower glove-side edge or at least throw them in the zone, even it was a bit middle. While the location wasn’t ideal, a middle-middle slider is a good pitch when hitters are sitting fastball.
Here’s an example of that working on a 0-0 count against Houston’s Yordan Alvarez, who is expecting a four-seamer and is fooled by the slider, even though it’s right down the middle.
Unfortunately, in the post-IL heatmap, he’s not generating any strikes, whether it’s in the middle or on the edges. As a result, hitters have been looking to lay off the slider, knowing that it won’t be a strike. San Diego did that on Friday, as his slider chase rate was only 12.5%.
As a result of his lackluster slider command, hitters have begun sitting on his four-seamer and changeup more. To make matters worse, since he isn’t throwing strikes with his slider, that puts more pressure on him to generate strikes with his fastball and changeup offerings (which he has done, based on the zone rates).
However, that can be an unideal combination, as hitters sitting on certain pitches will only pounce on them and produce base hits when they are thrown in the zone. The xwOBACON data shows the inverse benefit of Erceg throwing more strikes with his four-seamer and change to make up for his lackluster slider command.
His xwOBACON on those pitches has risen to .417 and .444, respectively. Before his injury, they were .364 and .300, respectively. Here is a look at his batted ball results chart via Savant that shows what hitters have done against his four-seamer and changeup when thrown in the zone (or close to it).
He’s given up four base hits and generated only one strikeout with his four-seamer and changeup post-IL. Thus, the slider command is not only hurting his breaking ball’s effectiveness, but it’s also having a domino effect on his other pitches as well, especially the four-seamer and changeup.
Thus, for Erceg to turn things around, he needs to regain control of the slider. If he’s able to do that, he’ll be able to be a little more fine with his four-seam and changeup command and won’t feel the need to throw so many strikes with it.
Final Thoughts on Erceg
While fans have Erceg’s tenure with the Royals in 2024 burned in their respective psyches, Erceg was far from a “dominant” reliever in his time with Oakland.
Before being traded over to Kansas City, he posted a 3.68 ERA and 1.20 WHIP in 38 outings and 36.2 IP. Those numbers are “okay”, but nothing close to what he did as a member of the Royals down the stretch.
So what happened in Oakland?
When examining his monthly splits, Erceg struggled with the A’s in May and June before rebounding in August with Kansas City. That can be seen in the table below.
In May, he posted a 4.82 ERA, and he followed that up with an even worse 5.14 ERA in June (highlighted by a 1.86 WHIP). However, his ERA fell back to 4.15 in July and then to 2.84 and 3.18 in August and September, respectively.
Now, let’s look at what Erceg has done this season in terms of monthly splits.
Like 2024, Erceg got off to a hot start with a 0.84 ERA (he had a 0.82 ERA last April). However, his ERA rose to 3.38 in May and is now up to 4.15 in June.
Thus, he’s showing the same kind of “bell curve” trend this season in Kansas City as he did a year ago in Oakland (and then Kansas City). This isn’t alarming by any means, as relievers can tend to show these trends, especially since their innings and sample sizes are so limited (especially compared to starting pitchers).
The good thing for the Royals is that Erceg is not the ONLY effective high-leverage reliever on this roster.
They have Estevez. John Schreiber can handle that work and is successful when his command is on (as he was in the Texas series). Angel Zerpa is getting more opportunities, as is Cruz, who has arguably been the Royals’ most underrated reliever in 2025.
Erceg may be going through some lingering issues from his lower back injury that may be affecting his stuff and command (especially with the slider). That said, this trend may be a typical pattern for Erceg that Royals fans will have to brace for, not just this season, but also in the years to come.
Thankfully, the Royals have the horses in the bullpen to get through this tough Erceg stretch, and the group should be even more ready for a run to the postseason when Erceg is locked back in, which may not be until July or after the All-Star Break.
Photo Credit: Brad Penner Imagn Images