One thing you can be sure of when you're a fan of a crappy baseball team is there will be people running in and out of the lineup you've never heard of all the time, and with the Twins' crappy options at shortstop given Pedro Florimon's inability to hit at all they've gone with the revolving door approach at the position. I should have hit on Eduardo Nunez after they acquired him, and may still do that, but with Danny Santana getting all the playing time lately it's time to figure out just who the hell this guy is.
John Sickels from minorleagueball.com ranked him the Twins' #15 prospect, Baseball America ranked him ninth, and Aaron Gleeman put him at #14. In short, he's a possible "shortstop of the future" and somehow we should be paying very close attention to and pulling for as hard as you can pull. If you click on that Baseball America link you can see his ranking within the organization the last four years has gone 25-20-11-9, so he's been improving and moving in the right direction. Sickels had estimated he'd be up late 2014, so he's a little bit ahead of schedule. But I'm getting ahead of myself. We should look at a little background.
Santana was signed out of the Dominican by the Twins as a 17-year old and who has had a rather rapid rise to AAA, playing at a below average age for the league at each stop. His career slash line is .274/.318/.393, which means he walks little and doesn't have much power - then again as a shortstop you don't necessarily need those things to be effective. He has some speed with 117 career minor league steals with a decent success rate of 69%, and although he strikes out a lot (career 18.5%) he had improved in 2012 and 2013 with a rate of 14.1% and 16.0% before ballooning up to 26% this year in AAA (in fairness, his first year at that level).
Since he's a shortstop, if he can put up his exact career numbers at the major league level, get a little better on the bases, and play above average defense he could conceivably grab the SS position on the team for the foreseeable future. That .274 average would have been 6th among all big league shortstops last year, while a .318 OBP would have been 7th and the .393 SLG 8th and his .711 OPS would have been 6th. Remember, the bar of shortstop offense is quite low outside of the freaks, so Santana's numbers, despite his lack of walks and power (just 25 career home runs, not a ton of extra base hits though he could be a 20 double/10 triple guy if everything breaks right), would make him a top 10 offensive shortstop. The steals are intriguing too, given that just 6 shortstops stole 20+ bases last season (Santana had 30 in 2013 at AA ball). It may be asking a lot, but looking at the numbers it's not out of the realm of possibility.
More important, however, is if he can play defense at a high level. His career fielding percentage at shortstop in the minors is .932, which is really, really bad. He was at .918 this season when he was called up, and even his best seasons were around .940-.950 which is still really, really bad. Like, dead last in the league bad. His range factor per game is 4.01, and as unreliable as that metric is (it's just assists+putouts / games) it's all we have for the minors. I couldn't find any leaderboards for it, but just checking a guy with range (Florimon, 4.63) and a guy without (Jhonny Peralta, 4.33) that number doesn't inspire confidence either.
That said, he's definitely a guy to keep a close watch on. The fielding could still develop and he's at least intriguing enough with his bat that it's worth giving him time. I wouldn't be against just handing him the starting job and pretty much letting him run with it for the year. If he can field and hit at the big league level the Twins may finally have a real shortstop.