Here are the prospects changing hands in today’s deal between Miami and San Diego as evaluated by my newly updated KATOH system. KATOH denotes WAR forecast for first six years of player’s major-league career. KATOH+ uses similar methodology with consideration also for Baseball America’s rankings.

Josh Naylor, 1B, San Diego (Profile)

KATOH: 4.4 WAR (80th overall)
KATOH+: 4.6 WAR (77th overall)

Though he turned 19 just last month, Naylor’s held his own in Low-A this year. Nothing in Naylor’s batting line is particularly great, but he also lacks a major weakness. He makes a decent amount of contact and draws an acceptable number of walks. His home-run total is a bit underwhelming for a first baseman, but’s made up for it by hitting a bunch of doubles this year. He’s also swiped 10 bases and played good defense, so KATOH gives him something of a pass for his underwhelming offensive numbers.

To help you visualize what KATOH’s projection entails, here is a probability density function showing KATOH+’s projected distribution of outcomes for Naylor’s first six seasons in the major leagues.

To put some faces to Naylor’s statistical profile, let’s generate some statistical comps for the teenage first baseman. I calculated a weighted Mahalanobis distance between Naylor’s Low-A performance this year and every season at those levels since 1991 in which a hitter recorded at least 400 batters faced. 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. A lower “Mah Dist” reading indicates a closer comp.

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.

*****

Luis Castillo, RHP, San Diego (Profile)

KATOH: 0.8 WAR
KATOH+: 0.7 WAR

Castillo has pitched very well at High-A this season, but has done so as a 23-year-old with an underwhelming strikeout rate. His 4% walk rate is encouraging — as are the merely two homers he’s allowed in 100 innings. But 23-year-old A-ballers who don’t miss bats rarely amount to much.

*****

Tayron Guerrero, RHP, Miami (Profile)

KATOH: 1.2 WAR
KATOH+: 0.8 WAR

Guerrero throws very hard, but has been unable to find much success in his seven years as a pro. Guerrero’s high strikeout rates in 2015 make him mildly intriguing, but there’s little room in KATOH’s heart for 25-year-old relievers with mediocre numbers.