There’ve Been Very Few Seasons Quite Like Daniel Murphy’s

One of the criticisms we get most often is that we sometimes overreact to small sample sizes. It’s true that we do, and it’s true that we probably shouldn’t, given how hard analysts have worked over the years to caution people against that very act. I can tell you this much: Our intentions are always good. And I can also tell you this: Players like Daniel Murphy are why we can’t stop.

Everyone wants to be first to see the breakout, and in the 2015 playoffs, if you’ll remember, Murphy homered seven times in 14 games. We can only identify that as a breakout in hindsight, but that streak sent everyone to the video. There was a search for a reason, a search for understanding, and that’s when the world learned of Murphy’s work with Kevin Long. The Nationals subsequently took the chance on Daniel Murphy, Quality Hitter.

Look, you’ve read about Murphy already. You know what he did. But do you really know what he did? They don’t make many players like this. There don’t exist many seasons like that. It’s really quite extraordinary.

One thing has always been true of Murphy: He’s been good at making contact. Quite good, as a matter of fact. A simple plot:

Nothing complicated there. Murphy struck out around an average clip as a rookie, but since then, he’s far more regularly put the ball in play. Strikeout rate is easy, but contact rate further supports the facts here. Over the PITCHf/x era, more than 500 different batters have come up at least 1,000 times. Murphy owns a top-40 contact rate, sandwiched between Nick Markakis and Angel Pagan. As strikeouts go, you’ve heard they’re at an all-time high. Murphy, the last two years, has maintained a strikeout rate in the single digits.

This is what’s new:

Through 2015, Murphy ran the same isolated power as — well, coincidentally, Justin Turner. But he was also right there with Martin Prado. The power, overall, was well worse than average. And then last year, Murphy’s ISO was in the top 20, incredibly above those posted by Miguel Cabrera and Chris Davis. Daniel Murphy finished with more home runs than teammate Bryce Harper. He finished with more home runs than any of his teammates.

I know this is old news, more or less. You already realized that Murphy broke out. You knew that Murphy could make contact, and you knew that Murphy started hitting for extra power. You also probably knew that Murphy’s in his 30s! The reason I’m bringing this up again is, despite it all, perhaps you still don’t see this for what it is. Murphy, last season, remained an extreme contact hitter. At the same time, he became something of an extreme power hitter. We’ve seen no shortage of players who’ve sold out for more dingers, but Murphy’s blend was most unusual. Few players have ever done quite what he did.

I looked at every qualified batter season since 1910. There are almost 12,000 of them. I concentrated on strikeout rate and isolated power, and for every single year, I calculated the league’s standard deviation. That allowed me to calculate, for every qualified batter season, a pair of z-scores. You’re smart, so you get it already, so here’s a plot, with Daniel Murphy’s 2016 season highlighted in red.

You see Murphy way over there on an edge. Contact hitters are on the left side of the x-axis, while power hitters are on the upper side of the y-axis. Murphy’s strikeout rate was 2.1 standard deviations lower than the average. Meanwhile, his isolated power was 1.6 standard deviations higher than the average. For reference, there are 180 seasons in the sample with strikeout-rate z-scores no greater than -2. The average of all those yields an isolated-power z-score of -0.5. Unsurprisingly, the most extreme contact hitters in history have hit for below-average power. We all understand that. This is how Murphy’s season was exceptional.

I decided to set a cutoff at -2, for the strikeout-rate z-score. Once I had all the most extreme contact hitters, I then sorted those player-seasons by the power score. Here’s the top 10!

Right there is your helpful historical perspective. It’s not that Murphy’s season was necessarily unprecedented. There’s been so much baseball, and plenty of weird things have taken place. Why, as recently as 2014, Victor Martinez was a better contact hitter than Murphy, and a better power hitter than Murphy. But Murphy’s season is still third on this list. It’s one of just eight seasons with an isolated-power z-score of at least +1. Tris Speaker was responsible for three of those eight seasons, all in a row, all before 1920. You’ve got Martinez, you’ve got George Brett, you’ve got Nomar Garciaparra, and then you’re basically out of recent comparables.

Michael Brantley is around, too, and so is the most recent version of Jose Altuve. I shouldn’t cut them off just because they didn’t make the table. But Altuve’s ISO z-score was 0.6. Brantley has topped out at 0.8. Murphy was just twice that high, relative to the average. His season was a freak-season, and the fact that it suddenly happened at the age of 31 makes it all the more bizarre. Murphy’s transition has probably been underrated in its degree of unpredictability. He’s hit for more power, and he’s lost nothing.

How much it’ll keep up, I have no idea. Neither does Murphy, and neither do the Nationals. Martinez stopped hitting for that power, but he also got hurt, and turned 36. Brett eventually made the Hall of Fame. Garciaparra remained amazing until he wasn’t. The only thing we can say for sure is that the Nationals feel a lot better about Murphy today than they did when they signed him. It’s not often a player gets to improve after his 30th birthday, but Murphy’s an exception, having turned into one of the game’s rarest assets. That small sample, it turns out, had real substance after all.