MLB Prospect Watch: Mariners’ Jarred Kelenic shows promise with September surge

Over the last couple of weeks, Prospect Watch has been dedicated to examining the Rookie of the Year Award races. Sometimes, those who don’t make the cut are as notable as those who do. Take, for instance, Seattle Mariners outfielder Jarred Kelenic.

Entering the spring, it was reasonable to bet on Kelenic factoring into the balloting provided the Mariners gave him enough playing time. All these months later, he’s going to have appearances in more than half of Seattle’s games, yet his candidacy has been betrayed by his performance. Coming into this week, he’s hit just .178/.258/.349 on the year, with his 70 OPS+ checking in as the lowest among the 17 rookies with at least 300 trips to the plate. (Yes, lower even than Colorado’s Yonathan Daza.)

If there is a silver lining to be found in Kelenic’s season, it’s that his numbers were a lot worse as of a few weeks ago. Indeed, he saved his best play for the campaign’s final month. In 19 games so far in September, he’s hit .257/.333/.600 with six (of his 13 total) home runs, four doubles, and three stolen bases (on two total attempts).

With the caveat that it’s a small sample size, there are some indicators that suggest Kelenic is finally, at last finding his footing as a big-league hitter.

This is an oversimplification of a complicated process, but you can tell a lot about the quality of a hitter based on a few critical outputs: how hard they hit the ball; the angle at which they hit the ball; and how they command the strike zone. It stands to reason that if a batter is consistently putting a charge into the ball at a somewhat optimal launch angle, and that they’re doing that while putting themselves into good counts, then they’re more likely than not to have at least some success at the dish.

In Kelenic’s case, those variables are mostly trending in the right direction. To wit, more than 50 percent of his batted balls in September have been measured at 95 mph or faster. He finished just one other month over 40 percent in that respect, and that was in June, when he was around 67 percent. The difference in those months is the angle. In June, he hit just 17 percent of his batted balls within the “sweet spot,” or between 10 to 30 degrees. So far in September, he’s up over 40 percent.

For some perspective on those marks, the only other qualified hitters who have exceeded 50 percent and 40 percent so far in September are Joey Votto, Kyle Tucker, Max Muncy, and Lourdes Gurriel Jr. That’s good company to keep, as all of them are above-average hitters.

Kelenic’s plate discipline remains mostly unchanged from a chase rate perspective — that is, how often he’s swinging at pitches outside of the strike zone. He is swinging more overall, however, and he’s making contact at his highest rate since May. Given his results, it’s hard to conclude that the tweaks he’s made at the plate aren’t working.

Of course, it’s to be seen if Kelenic can carry these gains into next season. For the first time in a while, though, he’s playing up to expectations.