Michael Wacha is Saving His Best Stuff (Especially With the Four-Seamer) for Last

The Royals took two of three from the Blue Jays in Toronto this week. Although their nine-game winning streak ended, a 10-2 Sunday win in the series finale helped Kansas City win its 12th game in its last 14 contests. Joel Penfield of KC Sports Network and I discussed that series and the Royals' winning ways in August on Thursday evening's Royals Postgame Show. 

While winning the Blue Jays series was nice, the Royals need to take, if not sweep, the weekend series against the Guardians to have any legitimate hope of making the playoffs. Thankfully, Kansas City set the tone on Friday by winning 3-0 in the opening game of the series in Cleveland. 

In fact, when it came to setting the tone on Friday, starting pitcher Michael Wacha was the one who led the charge for Kansas City.

In a masterful, eight-inning outing, the 35-year-old veteran allowed no runs, four hits, no walks, and struck out 10. His 10 strikeouts were the most for Wacha in a single game this season and his most since May 20th against the Boston Red Sox, when he struck out eight in six innings of work. The Royals All-Star outdueled the Guardians' Tanner Bibee, who allowed one run on seven hits and two walks and struck out five in six innings of work. 

The outing improved Wacha's ERA to 3.32 and WHIP to 1.10 this season in 170.2 IP. Wacha not only produced incredible results at Progressive Field against the Guardians on Friday, but he also posted some of his best metrics this season, especially with his four-seamer and changeup, his two primary pitches. 

When looking at his TJ Stuff+ summary from Friday, Wacha produced TJ Stuff+ marks over 100 on his two most-thrown pitches. That helped him generate strong metrics in his chase%, whiff%, and xwOBACON. 

Overall, Wacha sported a 52.4% zone rate, 34.7% chase%, 30.2% whiff%, and .341 xwOBACON against the Guardians. Those are all above-average marks. On his four-seamer, he not only posted a 101 TJ Stuff+ on the pitch, but also a 36.8% chase%, 20% whiff%, and .165 xwOBACON. For context, that TJ Stuff+ mark was seven points better than his season TJ Stuff+ mark of 94.

Here's a look at Wacha's overall TJ Stuff+ summary this season.

In addition to a bump in four-seamer TJ Stuff+ on Friday, Wacha also saw an increase in TJ Stuff+ on the changeup (102 to 99), cutter (97 to 93), the curveball (97 to 94), the sinker (91 to 88), and slider (106 to 101). So, with Wacha's stuff playing up in Cleveland, results improved, too. That improved stuff profile showed up on film in all 10 of his strikeouts, as seen in the video below. 

At 61-75, the Royals' playoff chances remain long. They are still 10.5 games behind in the AL Central, and their playoff odds remain stable at 0.1%. That said, the Royals are going to finish the season fighting, and it seems like the veteran Wacha is going to be one of the main players to lead that charge as Kansas City enters the final month of the regular season.

Is Wacha's Fastball Improving?

The fastball was the most eye-popping pitch from Wacha on Friday. While the whiff rate was modest compared to his other offerings (just 20%), he commanded the pitch effectively against the Guardians. 

Wacha threw the offering 39 times, good for a usage rate of 37.9%. He averaged 94.7 MPH on the four-seamer, a 1.7 MPH increase from his season-long mark, as well as a 2.2 MPH difference from his most recent outing against the Tigers at Kauffman Stadium on August 22nd. 

In fact, here's a look at his TJ Stuff+ summary from that outing against Detroit. 

Wacha's four-seamers in this most recent outing were a night-and-day difference from his August 22nd start. He not only threw far fewer pitches (21.9%) against Detroit, but he also had a much worse TJ Stuff+ (89), zone rate (47.%), and chase rate (27.3%). Surprisingly, his whiff rate and xwOBACON were better against the Tigers. 

Nonetheless, despite those mixed results, the velocity and TJ Stuff+ difference stick out. While Wacha flooded the zone enough to be successful against the Tigers (53.1% zone rate), the stuff and velocity metrics hinted that he may have been feeling some fatigue after a long season. However, the boost in four-seamer TJ Stuff+ and velocity on Friday showed that Wacha is NOT fatigued and could be leaned on as the Royals make a push in this stretch run of the 2026 season. 

Interestingly enough, Wacha has shown spikes in four-seam velocity at times earlier this season. You can see that in his pitch velocity chart by game this season below via Savant.

Wacha has seen positive spikes in velocity in July and early August, when the four-seamer surpassed 94 MPH. However, after such outings, he saw declines to under 93 MPH in his next starts. Thus, it will be interesting to see if Wacha can maintain that 94+ MPH velocity on his four-seamer in his next couple of starts, or if it can at least stay in the 93 MPH range. 

If that happens, Wacha may be able to keep improving outcomes on the four-seamer, which has been good at generating chase and CSW but has had mixed results at limiting xwOBA and producing whiffs. When looking at his four-seamer heatmap data against lefties and righties this year, Wacha at least has shown a propensity to command it effectively in the zone (up and near the edge of the zone).

Added velocity with that command will only make the four-seamer a more effective pitch, especially when it comes to results on whiff% and xwOBACON. 

On Friday, the former Texas A&M product really lived up to expectations on the edges of the strike zone against Cleveland. That strategy worked, especially with the increase in velocity on the pitch. Wacha produced plenty of called strikes and whiffs on the four-seamer, and when Guardians hitters did make contact, it resulted in outs, not base hits. 

The four-seamer has been a widely thrown pitch for Wacha this year, but it hasn't been an elite pitch by any means. That said, when he's able to get good stuff on the pitch and demonstrate strong command with it, he's found success on the mound, especially against AL Central teams. 

How Wacha's four-seam velocity and stuff fare in his next couple of outings could determine the Royals' slim playoff hopes, as well as whether or not Wacha will hit the 200 IP mark this season. If he does, it would be the first time in his career he hits that milestone. 

Can Wacha Be the Ace They Need (For This Year and Next)?

After the All-Star Break, Wacha has been even better than his 1st half self, which earned him a spot in the All-Star Game in the first place.

In seven outings and 43.1 IP after the All-Star Break, he has a 2.70 ERA and 0.95 WHIP. That is better than the 3.77 ERA and 1.19 WHIP produced in 19 outings and 119.1 IP. 

However, looking at his Statcast percentiles from the first and second halves via TJ Stats, Wacha has regressed after the All-Star Break. That is especially true in many batted-ball categories, including hard-hit rate and groundball rate. 

It simply seems like hitters are more locked in against Wacha after the All-Star Break. His GB%, SwStr%, barrel%, and Z-Contact% are all significantly down from his first-half marks. Thus, the veteran righty may be succeeding a bit due to batted-ball luck, rather than solely on his pitching skills. His .202 BABIP in the second-half illustrates that some lucky batted-ball results could be in play for Wacha. 

And yet, Wacha is doing what a veteran "ace" needs to do: he's carrying the Royals to victory.

He's carried them in their past two games, despite not getting much run support. The former Aggie has gotten just six runs of support in the past two games against Detroit and Cleveland, respectively. And yet, that lack of Royals run production hasn't deterred him on the mound, as evidenced by the wins. 

Even though Wacha isn't the prototypical ace, he's doing "ace-like" things for a Royals team that is in dire need of such a pitcher with that profile, both this year and next.

Cole Ragans is out until midway next year as he recovers from elbow surgery. Kris Bubic is no longer in the Royals organization. Noah Cameron has been a stud, especially recently, which makes fans wonder if he could be the Opening Day Starter over Wacha in 2027. 

However, he'll be starting just his third MLB season next year. Despite an improved pitching arsenal since moving to calling his own pitches, his four-seamer is arguably worse than Wacha's, based on TJ Stuff+ data.

Cameron is a great story and someone who will remain a key part of this Royals rotation long-term. He's proven that he can be a "pitcher" and not just a "thrower" this season. 

That said, for the Royals to get anywhere, whether in September or in 2027, they need a healthy, effective Wacha. Since 2022, he's been one of the most dependable pitchers in baseball, and often doesn't get much recognition for his consistency or impressive results on the mound. 

Granted, Wacha may or may not be the Opening Day starter next year, as so much depends on what the Royals do this offseason. (Will they sign a free agent ace?) That said, he's got to be an essential and effective part of the rotation that manager Matt Quatraro and pitching coach Brian Sweeney can lean on over a full season. 

Outings like Friday, especially with the impressive stuff and velocity, are a sign that Wacha is living up to, if not surpassing, those heightened expectations in Kansas City. 

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