I keep a little notebook next to my computer, so I can keep track of potential things to write about. Generally, topics break down into two categories: there are the topics that practically need to be written about, and there are the possible topics to monitor. Maybe those need bigger sample sizes; maybe those just need to become more interesting. Some of those topics turn into posts, and some of those topics never leave the piece of paper. I see that I crossed out something about Joe Ross. No idea what that was supposed to be.

For weeks, because of the notebook, I’ve been casually following Leonys Martin. I noticed in the early going that Martin didn’t look like himself: he was striking out a bunch, but he was also hitting more baseballs in the air. That seemed to me like something to follow, and wouldn’t you know it, but here we are, and Martin is still a fly-ball hitter. That’s odd because, in his entire major-league past, Martin was a ground-ball hitter. We’re more than a quarter of the way through the season, and now Leonys Martin appears to be a bat worth talking about.

If there was one thing we already knew about Martin, it was that he could play a mean center field. Between his range and his arm, Martin was one of baseball’s defensive elites, and that’s how the Mariners justified giving up talent to get him. The talk was about shoring up the Mariners’ defense, and as far as the offense went, you can see in the link that Jerry Dipoto referred to Martin’s “athleticism and speed.” I don’t know if the Mariners ever imagined Martin running a 125 wRC+. That’s where he is today, with a home-run total that has already equaled his previous career high.

Given that Martin officially stands 6’2, he always had a little more power to tap into, but as a Ranger, Martin was good for a wRC+ of 79. He slugged .361, and almost all of his positive value came out of other areas. The Mariners jumped on him as a bounce-back candidate, but Edgar Martinez must’ve seen something in there. The Mariners have made a project of Martin’s swing, and they’ve generated surprising results, if not outstanding ones. Though Martin has whiffed a little more often, he’s hitting the baseball with greater authority.

I made a pretty simple plot, showing data for hitters who’ve batted at least 150 times in each of the last two years. I calculated the changes in ground-ball rate, and I calculated the changes in hard-hit rate. I’ve taken the care to highlight Martin below:

Martin has shown one of the bigger drops in grounder rate, and he’s shown one of the bigger increases in hard-hit rate. Seems to me that puts him in a happy quadrant. A selection of his company in there: Daniel Murphy, David Wright, Victor Martinez, Yasmany Tomas. Everyone wants to hit the ball hard more consistently, but you don’t want to waste those quality batted balls on grounders. Martin has added some lift he didn’t have before.

If you know anything about data recording, you know that grounder rate can be kind of subjective. The same goes for hard-hit rate. So we can turn to Statcast, via Baseball Savant. Martin’s batted-ball speed has been a little bit better, but the real dramatic change is in where the ball has gone off the bat. Last year, 453 players hit at least 50 batted balls that Statcast recorded, and Martin ranked 396th in average launch angle. That is, on average, Martin’s batted balls came out nearly horizontal. So far this year, Martin ranks 37th out of 269. A table of the greatest launch-angle increases:

Lawrie is having a better offensive season. Soler definitely isn’t. Martin definitely is. By itself, this table isn’t good or bad; it just shows change. But Martin’s changes appear to be changes for the better, because right now he’s more productive than ever before. He has enough strength to succeed by putting the ball in the air, and the Mariners have come away with an all-around center fielder they might not have expected to have.

As you could probably guess, Martin is finding his power to the pull side. Through his first five years, two-thirds of Martin’s pulled batted balls were grounders, and he slugged .531. So far this year, half his pulled batted balls have been grounders, and he’s slugged 1.085. He’s not someone who’s likely to drill a ball 450 feet to left-center, because he doesn’t generate that kind of force, but selective power is better than no power. A pleasant side effect of Martin’s adjustments has been better visibility of the zone, which has allowed him to more often lay off pitches he can’t get the barrel to.

From a pitcher’s perspective, Martin has made himself more dangerous out over the plate. He can still get tied up inside, at least based on batted-ball speeds, so that could be the next step. Pitchers could mostly neutralize Martin’s strength if they gave him tight fastballs. The problem there is commanding that side of the plate, especially for righties. You risk balls running over the middle, and you risk balls cutting and hitting Martin in the hip. Again, it’s something to watch, just like Martin himself has been for a number of weeks.

Right now, Leonys Martin is a hitter. A real one, a dangerous one. The Mariners were happy to have him for his defense alone. Even they might’ve underestimated what was present underneath.