Not Quite Explaining Ryan Dempster

As you read this, the Boston Red Sox have the best record in all of major-league baseball, unless you’re reading this at least a few days after it was published. The Red Sox’s success is less of a surprise than the Blue Jays’ lack of success, but nobody expected Boston to start this well, and the organization is well on its way toward restoring the city’s confidence in the team. The Red Sox have gotten to this point by getting valuable contributions from their position players and from their pitchers. That will not be the only obvious sentence in this post.

We should pause to acknowledge what the Boston pitching staff has done to date. If the season were to end today, we’d all be left wondering, “wait, what?” But eventually we’d get over it and look at the statistics, and the statistics would show that the Red Sox have the highest team pitching strikeout rate in baseball history. As a team, the Sox have struck out 26.7% of opposing batters, and second place would be the…2013 Tigers, at 25.8%. Third place would be the…2013 Reds, at 23.3%. Fourth place would be the…2013 Royals, at 23.2%. So times have changed and strikeouts are up, but for the sake of perspective, the Red Sox as a team have a higher strikeout rate than both Nolan Ryan and Sandy Koufax. This is, of course, a team effort, but the greatest individual contribution so far has been made by Ryan Dempster.

Dempster signed as a free agent and is nearly 36. Last year he struck out just over 21% of batters. This year he’s struck out just over 35% of batters. He just faced the Astros, but that was the first time. Yu Darvish leads baseball with 49 strikeouts. A.J. Burnett is following Darvish with 48 strikeouts. Dempster’s in fifth, with 43 strikeouts, and this is measuring strikeouts as a counting stat, which is stupid. By rate, it goes Darvish, Max Scherzer, and Dempster. It’s not that Dempster has a history of pitching to contact, and it’s not that strikeout leaps are unprecedented, but generally you don’t expect a relatively old man to boost his strikeout rate by two touchdowns (and two extra points).

We can do a comparison between 2012 and 2013 rates of contact allowed, since I’m a big fan of looking at contact rate. We’ll set twin minimums of 20 innings pitched. The biggest increase between seasons so far belongs to Jason Hammel, at +11.3%. Uh oh! But we’re interested in the other end of the leaderboard. Homer Bailey’s contact rate has dropped by 7.0 percentage points. Darvish’s has dropped by 11.2 percentage points. Dempster’s has dropped by 13.5 percentage points, making it the biggest drop in baseball. Which isn’t a surprise, since it goes so neatly along with the gain in strikeouts. Dempster hasn’t let hitters hit the ball, so hitters have struck out.

Now is when we get to start following a formula. All right, so in truth we started some paragraphs ago. But here’s the general template:

1. Observation of statistical change
2. Analysis of phenotypic changes
3. Strong conclusion!

We can check off No. 1 — the statistical change is in Ryan Dempster’s strikeout rate. That has been appropriately observed, by us. Now is when we move on to looking for things about Dempster’s pitching that have changed, because we’re programmed to believe that all statistical fluctuations must be explained by something other than statistical fluctuation. We are wrong a lot! But still we must satisfy our own curiosities, and it’s not like I personally have anything better to do. This is actually what I do for my job. Forward we march.

Thankfully, there are some changes we can note. It’s not like someone like Ryan Dempster would’ve overhauled his mechanics — he’s very much established as what he is, since he’s a veteran who’s coming up on retirement, presumably. He hasn’t added a pitch or eliminated a pitch. Dempster hasn’t made big, sweeping changes, but I’ll note a few things that stand out. According to Brooks Baseball, Dempster has increased his splitter rate, from 13% to 18%. The splitter is a hard-to-hit pitch, a putaway pitch, so it makes sense that an increase in splitters would lead to an increase in whiffs. Against lefties, Dempster’s splitter rate is up from 19% to 27%, and strikeouts have followed. But the splitter rate hasn’t really budged against righties, and their strikeouts are way up, too, so we need to go a lot further.

One clue might be in Dempster’s heat maps of pitch locations. Here’s Dempster in 2012 against righties and Dempster in 2013 against righties, with the heat maps including all pitches:

Dempster’s always favored the outer half, but so far this season he’s gotten more extreme. He’s all but avoided the inner half, sneaking in only on occasion, and he’s also cheated just off the plate. Against righties, Dempster has been pitching to the outer edge, and edge pitches are good pitches, for pitchers. This seems like it’s something intentional.

And still, there’s more. Also from Brooks Baseball, let’s look at a chart of Dempster’s horizontal release points:

On this chart, 0 refers to the center of the rubber. A negative number is toward the third-base side. Dempster, this year, has shifted a little away from third base, toward the first-base side. It isn’t extreme and the ball’s still coming out on the same side as always, but a change is a change and we can support the chart above with screenshots. Here’s Dempster in 2012 vs. Dempster in 2013, and note the location of his front foot, relative to the rubber:

It’s very subtle, but so are most things. Clay Buchholz has also changed his release point. John Lackey has futzed around with his release points. Prospect Allen Webster changed his release point. Felix Doubront changed his release point. I might be seeing patterns where no patterns exist, but this could be a Red Sox pitching initiative. A change to one’s mechanics can be difficult to implement. A change in where a pitcher stands on the mound? That’s easy, and it could have consequences for location and platoon splits. I’ve just stumbled upon a much bigger article. For now, we’re still talking Dempster, and it seems like Dempster’s made a tweak that others on the same team have also made. Dempster’s tweak is correlated with individual success.

And there’s another thing. Against lefties, Dempster has doubled his splitter rate when behind in the count. He’s also greatly increased his splitter rate when ahead in the count. Against righties, he’s increased his slider rate when behind in the count, he’s increased his splitter rate when ahead in the count, and he’s increased his slider rate with two strikes. There also appears to be a significant shift away from sinkers in favor of four-seamers, although that could be a PITCHf/x thing and not truly a Dempster thing. The general point is that Dempster has worked toward greater unpredictability, and pitching is all about trying to not be predictable. It’s also about throwing good pitches, but. One notes that Dempster is sharing a clubhouse with catcher David Ross, and Ross seems to be an excellent game-caller and pitch-receiver. This is included as a potential, minor factor.

So on to the third and final part of our template. We see that Ryan Dempster’s numbers have changed. We see that Ryan Dempster’s pitching has changed, a little. IS THIS SUSTAINABLE GOING FORWARD? The answer is, I don’t know! The answer is always “I don’t know”, or at least it ought to be, because if we could predict baseball, we would’ve predicted Ryan Dempster’s early strikeouts.

It matters that we can identify little changes, but just because there are changes doesn’t mean we can nail down a causative relationship. The Red Sox, for their part, have expressed an interest in Dempster working deeper, and here’s what Dempster thinks about his own strikeouts:

“Strikeouts are overrated. I’m just trying to get outs. But I’ll take them however I can get them, and they’ve been coming, a lot of them, by the strikeout. I’m sure that won’t be the case all year.”

So Ryan Dempster isn’t exactly a Ryan Dempster believer, in this regard. He’s never had a month quite like this one, in terms of strikeouts. But it’s worth noting that, a year, ago, Dempster had 27% strikeouts through his first five starts. Over all his remaining starts, his strikeout rate dropped to 20%. What changed? Not really anything. Dempster’s results changed, but the whole time he was more or less still himself. From this point forward in 2013, Ryan Dempster is going to strike out a lower rate of batters. At issue is where his rate is going to settle, and we simply can’t know. The easy answer is it’ll settle around his career strikeout rate. But the changes identified above give hope that Dempster’s strikeouts could settle just a little bit higher. I’m sorry that this conclusion probably isn’t what you want, but that’s more your problem than mine. I’m not in the business of misleading you, and you shouldn’t be in the business of assuming that every significant change is accompanied by a causative significant change. That would be one lousy business.