The Case for Mark Trumbo

Rumors of the MLB trade variety suggest that Angels third baseman/hitter Mark Trumbo might soon be on the move to Arizona as part of a three-team deal involving also the White Sox. From what I’ve seen, the internet’s opinion (served hot, in take-out form) has been critical of Trumbo and the Diamondbacks for targeting him. We say Trumbo is written off unfairly thanks to sabermetric cynicism.

Time for us to be clear: we came of age in the present era of sabermetric explosion. Advanced stats are second nature to us, and beautiful; OBP is like the Mona Lisa and batting average is this thing (NSFW?). I’ve hated pitcher wins since I was 12 years old. So we know the criticism of Trumbo’s plate discipline is valid, that any OBP below .300 should be considered untenable by a sound-minded front office. But we don’t agree that Trumbo’s OBP will stay that way in the next few years. And we don’t think that the sabermetric community fully appreciates his power.

Recently we’ve been studying the year-to-year correlations of stats that express a hitter’s power. With pretty much the same data, we’ve also been studying aging patterns over the last ten seasons (2004-2013). In this article we’ll use some of our findings to talk about Trumbo. The whole shebang will be presented later this week. If you care about these things, keep in mind that we limited our research to player-seasons with at least 100 plate appearances.

Let’s start with the power stats. Below is a bar graph showing the year-to-year R-squared value for a bunch of different stats. The higher the bar, the more consistent the stat is from one season to the next. For now, focus only on the green bars; they are concerned only with home runs.


(Data taken from
Air = FB + LD
Contact = PA – (BB + K + HBP)

Home Runs per Contact (HR/Contact) has the highest R-squared value of the bunch. In terms of predictive power, it’s better than plain Home Runs, Home Runs per Plate Appearance (HR/PA), and Home Runs per Airborne Ball (HR/Air). It’s better than Isolated Slugging Percentage (ISO), itself way better than regular Slugging Percentage. HR/Contact isn’t difficult to calculate, either. You only need five stats: home runs, plate appearances, walks, strikeouts, and hits by pitch. (Hits by pitches? HBP, you know what I mean.)

HR/Contact is better because, more than any other stat, it separates a hitter’s power from the rest of his batting skills. It does not care about how many times a batter walks or whiffs, all it knows is how often the ball goes out when that batter does make contact. For Trumbo, that means appreciating his raw power free of context. By context we mean his prolific out-making. Bear with us here. We’ll re-contextualize him by the end.

Trumbo has been a regular player for three years, so we compared him to the best power hitters of those years (2011-2013), guys with at least 1000 PA over that span. Of the 30 players with the most home runs, Trumbo ranks 11th in HR/Contact. Of the 30 players with the highest ratio of home runs to fly balls, Trumbo ranks 12th in HR/Contact. Here’s a table of the latter group.


I like this group better because it has Trumbo’s potential future-teammate GOLDSCHMIDT in there for a nice comparison. (Click to engorge)

Based on this data, it’s easy to come up with crude tiers of raw power. (Crude things usually are easy, and fun.) Chris Davis and Giancarlo Stanton are clearly the elite mofos of the present day. The group from Adam Dunn to Mark Reynolds can claim to be distinct from those two above them and the morass below–Tier 2. Trumbo definitely belongs to Tier 3, however large you want to make that. Let’s say you’re Mother Teresa. You want to be generous with your rankings, so you define Tier 3 as anything above seven percent. Trumbo would sit in the upper half of that tier, above a lot of other people who are more celebrated than he. All told, only 21 players have a HR/Contact over seven percent, a.k.a. fewer than one player per team. If the Diamonbacks pulled this trade off, they’d have one, and another guy by the name of Goldschmidt, currently 23rd, a near-certain lock to crack the top 20 by the end of next year. That might just be the most powerful duo in the league.

You already knew about Trumbo’s power, though maybe you didn’t know the extent of it. Still, you’re skeptical of his plate discipline, and of his somewhat-related ability to avoid strikeouts. However, the aging data we’ve studied suggests that in the next two or three years Trumbo is likely to draw more walks and strike out less. Since 2011, his walk rate, according to Fangraphs, has risen steadily from 4.4% to 6.1% to 8.0% last year. His strikeouts have actually increased, however, bucking the traditional trend illustrated below.


(Data taken from

That steady decline across all ages bodes well for Trumbo, even though he hasn’t yet demonstrated a prolonged improvement. Batters find avoiding strikeouts easier as they age and gain MLB experience. Trumbo is a professional like the rest of them, and in his prime: the smart bet would be that he figures something out and shaves a couple of percentage points off his abnormally high strikeout rate. Especially if he bats in front of Goldschmidt, and you’re a believer in lineup protection (I think I am). Fewer strikeouts of course lead to more plate appearances ending in contact, so that Trumbo would get about two dozen more chances to put one in the seats. And if you think–with bias, presumably–that his gains in walk rate are bogus, then it stands he’ll have even more chances to make contact. That’s when Trumbo is dangerous.