The Astros Pulled Off A Trade Heist That Nobody Talks About
Nobody batted an eye when the Astros acquired Kai-Wei Teng from the Giants back in January. Odds are the right-hander's got your attention now.
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Each winter numerous trade happen across MLB that generate buzz, debate, and hot takes. Whether it be a prospect for a veteran or swapping major league talent, each trade will eventually be given a label of a winner and a loser. However, we rarely talk about smaller trades.
Swapping players at the bottom of the 40-man roster doesn’t generate the same buzz. In fact, most of these smaller trades go unnoticed by the common fan. The same was true in January this year when the San Francisco Giants traded Kai-Wei Teng to the Houston Astros for Jancel Villarroel, a Low-A catcher.
At the time of the trade no one thought much of it. You didn’t see articles breaking down Teng’s pitch mix or podcast describing how Teng would fit in Houston. He was a depth arm who appeared in 12 games across two seasons in San Francisco pitching to a 7.30 ERA and did not come with the level of intrigue that demanded headlines.
Well, Teng has your attention now.
Teng’s Early Success
Having an arm like Teng’s makes a manager’s job much easier. A chess piece that can bounce back and forth from the rotation to a bulk innings reliver helps a manager navigate injuries and depth across the span of 162 games. No matter the role, Teng has performed and helped keep Houston’s playoff hopes alive.
Across five starts Teng has a 3.27 ERA and 1.32 WHIP giving Houston valuable innings while they have struggled with injuries to their rotation. As a reliver, Ten has pitched to a 1.80 ERA and 0.85 WHIP across 13 games spanning 20 innings. Combine these roles and you have a 2.57 ERA, 4.06 FIP, and 1.10 WHIP across his first 42 innings in Houston.
Teng’s success all starts with his sweeper. A pitch that became the new hot thing in baseball a few years back but has since tapered off is still working for Teng. Since joining the Astros, Teng has improved the movement profile on his sweeper adding over an inch of horizontal break which has helped lead to a 32.8% whiff rate on the pitch.
You don’t see a ton of profiles that lead with a sweeper as the most used pitch but that is the case for Teng. Let’s start with his arm slot. At 23 degrees, Teng’s arm is not quite a “side-arm” slot but relatively low. Because of his arm slot, his sweeper moves on a horizontal plane that starts wider than a higher release point and the pitches east-west movement travels from inside (to a righty batter) to well outside the zone in a blink of an eye.
The picture above shows Teng’s release point (left) and where the pitch ultimately lands (right). Being able to pick up on the pitch, track the movement, and make quality contact is nearly impossible when Teng is hitting his spots and the stats prove that to be true. On his sweeper, batters have hit .101 with a .174 SLG and only a 85.7 mph average exit velocity. Even if you hit the pitch, it will likely be a weak grounder to the right side.
To me, the arm slot is crucial as a starting point for everything Teng does. Let’s look at the other arm slots that throw a sweeper from 22 degrees to 24 degrees. Zack Wheeler, Chris Bassitt, Bryan Woo, Jake Irvin, Brady Singer, Joe Ryan, Seth Lugo, and Chase Dollander. OF those eight, only Lugo has a whiff rate under 25% while five have a whiff rate over 30% on their sweeper.
For Teng’s sweeper to be effective it needs to be well located. If the pitch does not move enough or catches too much of the strike zone there could be trouble.
Via Baseball Savant
The heat map above shows the location and contact of Teng’s sweeper. Rarely landing in the zone but still remaining effective. What’s even more impressive is that Teng does not only use the pitch to fool righties casing low and away, but he utilizes it against righties, too.
Because of the movement he generates off his sweeper he is able to have his 94 mph four seamer play up. His fastball isn’t a high velo or IBV pitch. By most standards it’s rather average. However, all the pitch needs to do is keep players honest and set up his sweeper. Tunneling these two pitches gives a batter fits as they look similar out of the hand before his sweeper’s late break darts away from his fastball plane.
This one-two combo gives Teng an avenue for sustained success. His sweeper is a lethal pitch that should give high at least a floor that will keep him in the big leagues. What role he eventually settles into will all come down to how he grows from here.
Next Steps and Room for Improvement
Although Teng’s sweeper often lands outside of the zone, I don’t view it as a problem. He has racked up 25 strikeouts on his sweeper to nine walks. Of those nine walks, most were great pitches and better takes by the batter. Sure, his sweeper can get him behind in accounts at times, but considering it is the pitch that makes establishes his value I would not tinker with it.
Teng has struggled with walks at the major league level and at times in the minors. His 4.07 BB/9 this season is the best of his short major league career and, in my opinion, a number I’d be comfortable with. I would be afraid of losing effectiveness if the focus was simply throwing more strikes.
Instead, Teng needs to find a way to improve his secondary pitches. His four-seamer only gets so much help from his slider and often gets hit hard. I’m not sure how much he will be able to improve his four-seamer, which is a good enough pitch, which is why we are seeing him lean on his sinker more.
While I like the idea of a sinker, which could help generate more groundballs, I’m not sure if it will work for Teng. Pitchers with similar arm slots that throw sinkers don’t always find a ton of success on the pitch, outside of Logan Webb. To me, the pitch that Teng could use to elevate his game is his changeup.
The first clip in the video above shows Teng’s changeup. A beautiful late dart away from the barrel like that would unlock Teng and help him take the next step. The issue is most of his changeup’s aren’t this tight and fall flat which is why I don’t think he trust the pitch right now.
Teng has handled righty batters holding them to a .446 OPS but lefties have posted a .766 OPS off him. If Teng can get a better feel for his changeup and see a higher percent look like the one in the video it would help give him a pitch to neutralizes lefties and allow him a greater chance of sticking as a starter.
If not, his best role could be as a bullpen arm. Which, all things considered, is not a negative. While the Astros would love to see Teng develop into a starter, having him land in the bullpen would still be a win. Houston needs arms that project into the future as the teeter between still in a contention window and moving into their next phase.
In order for Teng to have an effective enough pitch mix to work through a lineup multiple times and remain consistent, he will need another pitch he is comfortable with that can avoid barrels. I can take the above-average walk rate so long that consistent hard contact ticks down.
Final Thoughts
The average baseball fan probably looks at Houston’s current rotation and leaves unimpressed. I was guilty of this earlier this season. However, Spencer Arrighetti, Teng, and Peter Lambert are showing that the Astros are able to identify, develop, and tweak arms enough to find production.
There’s still work to be done with Imai, who looks more settled, and Burrows but no front office will hit on 100% of their move. The Astros best chance at silencing the Yordan Alvarez and Jeremy Peña trade rumors will come down to having enough quality pitching to get them back to better health. Teng is a major factor in that regard.
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