Projecting Yoan Moncada

After they shipped Todd Frazier to the Yankees in exchange for prospects earlier this week, the White Sox replaced him on their roster with Yoan Moncada. Moncada was hitting a healthy .282/.377/.447 at Triple-A, highlighted by his 12 homers and 17 steals. He hits for average, hits for power, steals bases, and even draws walks. Very few players can hit like Moncada does while also providing value in the field and on the bases. That’s why he was a fixture at the top of midseason prospect lists this summer. Baseball America and Baseball Prospectus both ranked him No. 1, while Keith Law put him at No. 13.

But for all his strengths, Moncada has some weaknesses that we shouldn’t overlook. Most notably, he strikes out a bunch. Moncada’s struck out in over 28% of his trips to the plate this year. Though it’s been somewhat hidden by his high batting averages, Moncada has had a lot of trouble making contact against minor-league pitchers. This suggests he’ll have even more trouble doing so in the big leagues, which is exactly what happened in Boston last September when he struck out 12 times in 20 plate appearances.

There’s also the matter of Moncada’s defense. He’s primarily played second base since emigrating from Cuba, and the prognosis for minor-league second basemen isn’t great. The fact that he’s already been deemed “not a shortstop” is a knock against him in KATOH’s eyes. Furthermore, his defensive metrics at second base aren’t great. He’s been right around average there by Clay Davenport’s fielding data this year and was several ticks worse than average last year. This suggests he may not be a defensive asset in the infield.

My KATOH system pegs Moncada for 8.6 WAR over his first six seasons by the stats-only method and 15.6 WAR by KATOH+, which incorporates his No. 1 prospect ranking from Baseball America. Those marks place him 20th and third, respectively, among prospects. Everybody loves Moncada, including KATOH, but KATOH loves him a little less than everyone else.

To put some faces to Moncada’s statistical profile, let’s generate some statistical comps. I calculated a Mahalanobis distance between Moncada’s Triple-A performance and every Triple-A season since 1991. Given the scarcity of elite second-base prospects — let alone ones who look like Moncada — I included prospects who played other more challenging defensive positions, including: second base, third base, shortstop, and center field.

In the table below, you’ll find the 10 most similar seasons, ranked from most to least similar. The WAR totals refer to each player’s first six seasons in the major leagues. Please note that the Mahalanobis analysis is separate from KATOH. KATOH relies on macro-level trends, rather than comps. The fates of a few statistically similar players shouldn’t be used to draw sweeping conclusions about a prospect’s future. For this reason, I recommend using a player’s KATOH forecast to assess his future potential. The comps give us some interesting names that sometimes feel spot-on, but they’re mostly just there for fun.

As noted above, Moncada had a lot of trouble making contact against high-minors pitching, and it’s unreasonable to expect him to have any less trouble as a rookie in the big leagues. That doesn’t mean he can’t still be productive, of course, as his power, speed, and walks are bound to generate value. Some of the best players in baseball produce considerable value with strikeout rates well over 25%, including Cody Bellinger, Aaron Judge, and Miguel Sano. For what it’s worth, Steamer projects Moncada for .230/.310/.366 (80 wRC+) for the rest of the season with a 31% strikeout rate. That isn’t a terrible baseline expectation, but given his outstanding physical tools, don’t be surprised if Moncada blows past those numbers.