Yesterday, the Washington Nationals promoted infield prospect Wilmer Difo to the major leagues to fill the roster spot vacated by the injured Jayson Werth. As Dave Cameron pointed out yesterday, this move was something of a head-scratcher. Although Difo’s a fairly well-regarded prospect, he wasn’t exactly pushing for a call-up. He had all of 14 games above A-Ball to his name, and only 25 more above Low-A. Even stranger is that there isn’t a ton of playing time to be had in the Nationals infield. Ian Desmond, Danny Espinosa and Yunel Escobar seem to have shortstop, second base and third base covered until Anthony Rendon’s ready to return from injury.

Although he’s spent the entirety of his professional career in the low minors, Difo’s done nothing but hit the last couple of years. He spent all of 2014 in Low-A Hagerstown, where he hit a strong .315/.360/.470 with 49 steals. This year, he split time between High-A and Double-A, and hit an even better .315/.367/.520. Before you get too excited about those numbers, though, I’ll point out that Difo is already 23 years old. Most prospects worth their salt are at least a year or two removed from A-Ball by their 23rd birthdays. This isn’t to say that Difo is doomed as a prospect. Plenty of late-blooming prospects have gone on to have long and productive careers; but in the world of A-Ball prospects, you’d much rather a guy be 19 than 22 or 23.

Although he didn’t reach full-season ball until last year, Difo’s been around for a while. The Nationals signed him as an 18-year-old out of the Dominican back in 2010. However, despite strong offensive showings, they moved him very slowly through the system. The Nats kept him in the Dominican Summer League until July of his age-19 season, and didn’t move him out of American Rookie-ball until he was 21. This set him up to play his first full year in full-season ball last year at age-22.

Difo’s loudest tool is his speed, which grades out as a 70 according to Kiley McDaniel, and enabled him to steal 57 bases in 68 attempts between this year and last. There’s more to Difo than just his speed, however. He also showed an intriguing combination of power and contact in his minor-league stay. Difo racked up 52 extra-base hits last year, including 14 homers. This year, he logged 19 extra-base knocks in 33 minor-league games before his call up. Difo complemented this modest power by striking out a mere 12% of the time. Through this blend of contact and power, Difo put up a 139 wRC+ in spite of his 6% walk rate.

Difo’s offensive numbers have been pretty good, but KATOH still isn’t too thrilled about the switch-hitter’s future prospects. Based on his 2014 stats, my model forecasted him for just 1.5 WAR through age-28. KATOH’s pessimism had everything to do with his age relative to his level. KATOH penalizes players for their age, making it darn near impossible to earn a good projection as a 22-year-old in Low-A.

A list of comps should make KATOH’s reason for pessimism a little more clear. Using league-adjusted, regressed stats, along with age, I calculated the Mahalanobis distance between Difo’s performance between this year and last and every A-Ball season since 1990 in which a batter recorded at least 400 plate appearances. Below, you’ll find a list of historical players whose performances were nearest and dearest to Difo’s, ranked from most to least similar.

*Batters who have yet to play their age-28 seasons.

And here’s a list containing only players who made the majority of their starts at the middle-infield positions.

*Batters who have yet to play their age-28 seasons.

There are a few successful players in this bunch. Julio Lugo turned into a steady, everyday player, and Jean Segura has shown similar promise at times. But the majority of these players ultimately had little or no big-league impact. KATOH is pessimistic on older A-Ball hitters with Difo’s skill set for a reason: many of them never pan out. Based on this data, Difo stands a better chance of taking after Motorboat Jones — who was an actual person in the 1990s — than Julio Lugo.

Difo was pretty far off the grid, so neither Steamer nor ZiPS have ready-made 2015 projections for him at the moment. But I’m sure the projections will be pretty uninspiring if and when they do turn up on his player page. Over at Baseball Prospectus, his 50% PECOTA projection is a weak .232/.268/.320. With few exceptions, A-Ball hitters would be eaten alive by major-league pitching. And the projection systems’ major-league equivalencies treat data from the low minors accordingly.

Difo’s unlikely to contribute much offensively this year, but at the very least, he should provide the Nats with sturdy defense. Most evaluators seem to think he’s capable of playing shortstop in the majors, and he’s also gotten some reps at second base in the minors. He played 66 games at the position last year, and Baseball America deemed him the best defensive second baseman in the South Atlantic League at season’s end.

Kiley gave Difo a 45+ FV grade heading into the year, which equates to a borderline everyday player. Difo may reach that ceiling someday, but here in 2015, it doesn’t look like he’s quite there yet. Nonetheless, the Nationals apparently think he can be of some use today as a backup infielder and pinch runner. Contact-oriented hitters like Difo tend to handle the transition to the majors pretty well, so maybe they’re hoping he’ll be able to give them something like an 80 wRC+. That would make for a useful player given his speed and defense, but going by the data, there’s no guarantee he’ll even clear that low offensive bar. Difo’s an interesting — albeit fringy — prospect who stands a decent chance of being a useful utility infielder someday. But there’s little reason to think he’s ready to be that player right now.