The Cubs promoted 20-year old Javier Baez to AA Tennessee this past weekend after a scorching half-season or so in Daytona. Baez's power output in the Florida State League was pretty incredible, as he hit 17 homers in a very pitcher-friendly league despite his young age. Last season, he hit 16 homers in 80 games spread between Peoria (in the Midwest League, which is also very hitter friendly) and Daytona. It's hard to deny that he has some of the best power in all the minor leagues, Miguel Sano and Joey Gallo notwithstanding. It's also really hard to overlook the fact that he strikes out a lot and walks far less than you might expect.
The "comparable player" most often tossed around for Baez is Gary Sheffield. And Baez's swing does look like Sheffields's. To me, though, it's an unsatisfying comparison. Prospects tend to get comp'ed to hall of famers because we as fans have easy access to the way that great players looked on the field. A pitcher who throws effortlessly from the stretch tends to get compared to Greg Maddux even if Rodrigo Lopez would be a better fit. I like to think of this as the Charlie Morton problem. At some point prior to the 2010 season, Morton decided to completely ape Roy Halladay's delivery. The problem is that he was still Charlie Morton. If a top prospect comes along with a similar windup and repetoire one of these years, which of Morton and Halladay do you think he will be compared to?
While Javier Baez might look like Gary Sheffield, the output isn't remotely similar. Sheffield hit for a ton of power, of course, but he rarely struck out, even in the minors, and he walked at an average rate. So what happens if we de-emphasize the visual aspect of the comparison and weigh the outcomes more heavily?
Major League Comps
It's not that difficult to find to find at least semi-productive major leaguers who display a similar skillset as Javier Baez at the plate, though most of them don't play shortstop. The names that jump to mind are Michael Morse, Mark Trumbo, pre-2013 Chris Davis, Alfonso Soriano, and (gulp) Tyler Colvin. All these guys have struggled mightily with not enough walks and too many strikeouts throughout their careers, but can absolutely crush. They are also, for the most part, hulks who hide on defense in corner spots. Baez is only 6'0" or 6'1", depending on who you talk to, and 200 pounds. The Cubs have said they think he will remain a shortstop. As we move up the defensive spectrum, the names that fit the bill become more rare. Third baseman Will Middlebrooks might qualify, though it remains to be seen whether he can stick in the majors. Adam Jones is a bit closer, but he is definitely a notch above any of the names mentioned thus far in terms of making making contact. Carlos Gomez seems to work, given his power surge in the past year and a half.
At shortstop, the one comparable that stands out to me is Ian Desmond. Desmond is also bigger than Baez, but he is athletic, plays a mediocre shortstop, and has all the requisite K's and dingers. Bill Hall works if you squint, though he managed to increase his walk rate to a nearly league average level after a couple of years in the bigs.
Minor League Comps
While the above names have pretty similar outcomes at the major league level, if you look at their minor league numbers, they tend to diverge significantly. Most managed close to an average walk rate in the low minors, even if they struck out a lot. On the other hand, few of them come close to the power that Javier Baez has shown at such a young age. Take Desmond for example. He managed to make it to AA in his age 20 season despite not being a highly regarded prospect, and his career line through that season featured 6% BB's and 20% K's, but only a .104 ISO. He was sent back to A+ at 21, and managed to up his walk rate considerably (10.6%), and show more power (.164 ISO).
It would be satisfying, if not particularly meaningful, to find a player who put up similar results to Baez through age 20 and went on to a successful pro career. I looked through the leaderboards at high-A over the past decade or so trying to find someone who looked like a reasonable comparison. It turns out that it is really hard to find a big-leaguer who hit for as much power while walking as infrequently as he does with the strict age/level criteria that I imposed. For the most part I ignored everyone who flamed out in the minors, as this wasn't a rigorous exercise wherein I tried to estimate Baez's probability of major league success. Peanut Williams, Jarek Cunningham, and Motorboat Jones comps aren't going to do anyone any good. I just wanted to at least one decent player with the similar boom or bust stat-line at a similar age. It turns out this is a pretty difficult task.
The nightmare scenario is Brandon Wood, of course, who it 43 homers in the Cal League at age 20, yet to-date has only managed to earn 750 plate appearances at the big league level. Through his age 20 season, Wood managed 8% walks, 22% strikeouts and a .243 ISO. Translated from the Cal League to the less hitter-friendly environment in Florida, these numbers probably aren't that far off from Baez's 5% BB, 22% K's, and .248(!) ISO. Keep in mind that Baez's 694 professional plate appearances thus far are dwarfed by Wood's 1400+ through age 20, so a bit of regression should be expected in all three categories for Baez relative to Wood. Wood was also a pretty highly regarded prospect, making BA's list prior to his breakout year in 2005 and for three years thereafter.
Surely we can write off Wood's numbers as a Cal League artifact and find someone to make this exercise more optimistic, right? Well, try this one on… Matt Kemp. Kemp spent his entire age-20 season in the Florida State League. Through that season, he posted a 5% walk rate, 20% K's, and a .211 ISO in 1100+ plate appearances. Kemp was never that highly regarded as a prospect, as he managed to crack the top 100 only once. In his age-21 season he upped his walk rate considerably and made it to AAA. At the Major League level, Kemp has struck out a lot, but essentially managed a league-average walk rate to go along with good power while playing a below-average center field. Kemp is much taller than Javier Baez, of course, at 6'4", but we are letting that take a backseat here.
This is not to say that Javier Baez will follow Kemp's path and turn into an all-star. I simply wanted to find someone who produced similar outcomes at such a young age: allergic to walks, poor contact, and prodigious power, who turned out to be a good player. Along the way, I was hoping to perhaps come up with a better comp than Gary Sheffield for those of us that focus more on outcomes than appearances. I think that Desmond and Kemp work in that regard.