Let’s revisit some previous analysis on Pittsburgh Pirates players Trevor Williams and Elias Diaz.

My favorite kind of article to write is “player has a problem, let’s find the solution or issue”. Looking through my articles here at Armchair proves that. This season alone I have written five such articles. As fun as they are to write, I tend to write them and then forget about the article. Never to return to see if I correctly diagnosed the issue or completely whiffed. That ends today.

Earlier this season I wrote about the possible hitting change of Pittsburgh Pirates catcher Elias Diaz in May and the early June struggles of pitcher Trevor Williams. Williams has made a drastic bounceback and Diaz has continued his success. It’s time to see if my analysis was worth a damn…

Elias Diaz swing change

Then

At the time of this article, Elias Diaz and Francisco Cervelli comprised the best hitting catcher duo in baseball. Not much has changed since then, the Pirates’ combo lead second place by a full 1.6 WAR. Cervelli is still hitting well but has missed some time, giving Elias considerable opportunity at the plate. Diaz has cooled down a bit since then. In May, Diaz was hitting .383/.442/.553 helped by a .400 BABIP. Coming up Diaz was a glove-first prospect without any semblance of a bat. With only 60 ABs under his belt, it had seemed that Diaz had transformed himself into a hitter. At the time, I suggested that Diaz had become more selective with his swings. It seemed like Diaz was trying to be more selective with the pitches he hit and avoid the ground balls that had been such a big part of his hitting last season. Basically, it looked like he was joining the launch angle revolution. Although not to the extremes of other players.

Now

One hundred and forty-ish at-bats later and all those things still hold true. Diaz has cooled off a bit (.283/.333/.472) and the BABIP has come back to earth (.295). This is still drastically better than Diaz has ever hit at any level. In fact, he’s a damn good hitting catcher. Elias is seventh in catcher WAR and has the fifth highest wRC+ among catchers with at least 200 at-bats. The launch angle, exit velocity, and fly ball rate have all remained relatively the same from May. These numbers are definitely different from Diaz’s past.

All the numbers say Diaz has changed his approach. He’s changed the balls he swings at.

Elias Diaz swing heatmap 2018 from fangraphs.com

Elias Diaz swing heatmap in 2017 from fangraphs.com

After 200 at-bats I think it’s safe to confirm that Diaz has changed his approach. His focus is now on lifting the ball to avoid those pesky grounders. Put one in the “Nailed it!” column for me.

Trevor Williams’ changeup problem 

Then

Williams started off the season fairly well but ran into some trouble in the middle of May and June. For four starts he struggled and could barely pitch through the fifth inning. His ERA shot up and the Pirates experienced one of their most drastic skids of the season. Upon review, I determined that his changeup was to blame for his issues. Trevor had been missing more with the changeup and it was getting absolutely smoked. There was some bad luck (.360 BABIP) but it seemed like his changeup had lost some of its snap from earlier in the season.

Now

After writing that article Trevor began to right himself, especially after the All-Star break. He had a 20+ inning scoreless streak going before it was finally broken up in early August. It was almost like a different Trevor took over for pitching. He went from terrible fourth starter to ace levels of production.

Honestly, an entire article could be devoted to what changed. The simplified version is Trevor figured out how to put lefties away. When I wrote my article it was hard to tell that the lefties were crushing Trevor because everyone was crushing him. Two months later the difference is startling.

Good Starts (GS) ERA Bad Starts (BS) ERA GS OPS BS OPS GS BABIP BS BABIP
Vs R 2.91 6.10 0.705 0.841 .300 .412
Vs L 2.30 17.36 0.556 1.401 .200 .435

 

Fixing changeup control doesn’t lead to that much success. In fact, his changeup in post article starts looks a lot like the changeup from his bad starts (3.53 and 3.41 average vertical drop respectively). He did clean up the control though.

Pitch% heatmap on Changeups (May 20th-June 12th) from fangraphs.com

Trevor Williams Changeup heatmap from 06/13-08/16 from fangraphs.com

Besides shutting down lefties, Trevor has had success in some other key spots. Williams’ LOB% has skyrocketed to the 80-95% range in July and August. His previously poor luck has turned around (BABIP of .247). The home run rate has taken a dip but he’s also striking out fewer batters. Clearly, there’s more to it but requires more digging, come back in the offseason for that analysis.

I think it could be safely said that there is more than improved changeup movement and location going on. We’ll put this article in the “I got it wrong column” or “only found one of the problems ” if you’re feeling generous.

Analysis isn’t easy, it requires a lot of digging. Sometimes trial and error and always tons of time. Regardless, I always find it interesting one way or another. So I’ll continue to learn from mistakes (writes down “always check platoon splits”) and I’ll gladly take not being completely wrong on those past two articles.

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Author Details
Content Contributor for the Pittsburgh Pirates , The Armchair All-Americans LLC
I grew up in the only hilly part of Indiana, an unholy place where Reds, Cardinals, and Cubbie fans all live in semi-harmony. The first 20 years of my life were abysmal as I never got to see a winning season from my beloved Pirates. Today I live in bliss as I allow my baseball addiction to take over every aspect of my life.
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Content Contributor for the Pittsburgh Pirates , The Armchair All-Americans LLC
I grew up in the only hilly part of Indiana, an unholy place where Reds, Cardinals, and Cubbie fans all live in semi-harmony. The first 20 years of my life were abysmal as I never got to see a winning season from my beloved Pirates. Today I live in bliss as I allow my baseball addiction to take over every aspect of my life.
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