Projecting Nationals Right-Hander Reynaldo Lopez

Less than a month ago, the Washington Nationals called up top prospect Lucas Giolito, with the hopes that he’d fill a hole in their rotation. However, as often happens with promising young pitchers, Giolito looked a bit overmatched in his first taste of the big leagues. He recorded more walks than strikeouts in his two starts with Washington, and was subsequently sent back to the minors to further refine his breaking stuff. Giolito will surely be back sooner rather than later, and still appears to have a bright future ahead of him. For now, though, the Nationals are turning to another electric young arm: hard-throwing 22-year-old Reynaldo Lopez debuts tonight against the Dodgers.

Lopez was signed out of the Dominican back in 2012, and his stuff has landed him on top-100 prospect lists for a couple of years now. But up until this season, he his minor-league performance hadn’t quite matched up with his stuff for any extended period. He spent the 2015 season in the High-A Carolina League, where he posted a mediocre 4.09 ERA. His peripherals suggest he pitched much better than that, but his 23% strikeout rate still underwhelmed.

He opened 2016 at the Double-A level, and soon began missing bats at a rate commensurate with his stuff. His 30% strikeout rate is tops among qualified Double-A pitchers this year. He also managed to keep his walk rate under 8%. Though he wasn’t super sharp in his two most recent starts at the Triple-A level, the body of Lopez’s 2016 campaign bodes well for his future in the bigs.

KATOH was way down on Lopez heading into the year. My system pegged him for just 1.3 WAR over his six years of team control, making him an afterthought of a prospect. Adding his 2016 numbers to the mix, his forecast improves to 3.2 WAR, which makes him a top-150 prospect. KATOH’s still lower on him than any major outlet, but Lopez’s strong half-season in Double-A has substantially closed the gap.

To put some faces to Lopez’s statistical profile, let’s go ahead and generate some statistical comps for the undersized — but hard-throwing — righty. I calculated a weighted Mahalanobis Distance between Lopez’s Double-A performance this year and every Double-A season since 1991 in which a pitcher recorded at least 350 batters faced. In the table below, you’ll find the 10 most similar seasons, ranked from most to least similar. In generating Lopez’s comps, I only considered pitchers who cracked Baseball America’s top-100 list either before or after the season in question. This is intended to act as a proxy for “good stuff,” which Lopez certainly has. 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.

Though he’s yet to prove himself at the Triple-A level, Lopez’s strong Double-A performance suggests he might be ready get big league hitters out. Even if the currently injured Joe Ross winds up crowding him out of the rotation, Lopez could slot into Washington’s bullpen, where they’re reportedly looking to upgrade. Lopez could wind up playing a big role for the Nats as soon as this year, starting as soon as tonight.