What Might Mookie Betts Be?

Over the weekend, the Red Sox summoned Mookie Betts from Triple-A; he made his big league debut last night, going 1-3 with a walk. While no single game will ever reveal much about a player’s skillset, the process by which he approached the game seems to fit with his minor league profile:

He didn’t chase pitches; he swung at only two of 11 out-of-zone-pitches.

He makes contact; he put the bat on the ball on all eight in-zone swings.

According to MinorLeagueCentral, Betts only swung at 34% of the pitches he was thrown in Pawtucket, and he made contact on 88% of his swings. Minor league data isn’t as reliable as major league data, but in general, swing and contact rates are pretty easy things to track and should at least be in the ballpark. While Betts will almost certainly see more in-zone pitches and be forced to swing more often in the big leagues, he has shown a pretty disciplined eye at the plate, and we shouldn’t expect him to expand the strike zone even against big league pitching.

And swing/contact rates do tend to carry over from the minors to a decent degree. For instance, if we look at the other prospects of note who have been promoted from the International League this year, we see that their swing and contact rates in the big leagues were in the same general range as their were in Triple-A.

Player	AAA Swing%	MLB Swing%	AAA Contact%	MLB Contact%
Gregory Polanco	40%	39%	77%	78%
Tommy La Stella	42%	44%	88%	83%
Kevin Kiermaier	51%	48%	82%	76%
Danny Santana	50%	51%	79%	81%

Betts will have to swing more and probably make less contact, but even if we regress his numbers back to something like a 40% swing rate and an 85% contact rate, that still gives him a chance to be a hitter who controls the strike zone in a significant way. For comparison, here are the major league hitters who are around those numbers.

Name	Team	PA	Swing%	Contact%	BB%	K%	ISO	BABIP
Kyle Seager	Mariners	324	42%	83%	8%	19%	0.212	0.317
Coco Crisp	Athletics	265	40%	86%	14%	13%	0.157	0.309
Anthony Rendon	Nationals	343	41%	86%	8%	16%	0.201	0.306
Casey McGehee	Marlins	354	40%	86%	10%	15%	0.076	0.362
Christian Yelich	Marlins	290	39%	83%	11%	20%	0.165	0.314
Ben Zobrist	Rays	306	39%	85%	11%	14%	0.145	0.281
Jason Heyward	Braves	359	42%	83%	12%	16%	0.129	0.278
Jimmy Rollins	Phillies	345	40%	84%	11%	17%	0.136	0.280
Joe Mauer	Twins	331	39%	85%	10%	18%	0.081	0.332
J.J. Hardy	Orioles	297	41%	84%	4%	16%	0.072	0.339
Omar Infante	Royals	267	41%	87%	6%	12%	0.115	0.265
Average		316	40%	85%	10%	16%	0.135	0.308

By and large, these guys strikeout less than the average hitter, walk a little more often, and have below average power. It is a list, not surprisingly, made up of middle infielders or guys who have shown significant defensive value, and many of them are also good baserunners. This is the kind of skillset that is often found among athletic players who might not be great hitters but are quite valuable across the board. As a group, they’ve averaged a 109 wRC+ this year, but have combined for +20 WAR in just under 3,500 plate appearances, or an average of about +3.5 WAR per 600 PAs. These guys are not superstars, but quality above average big leaguers with a broad base of skills.

Of course, because we only filtered based on swing and contact rates, there’s a pretty wide variance in production. Saying Mookie Betts is comparable to a group that includes Anthony Rendon is exciting; noting that it includes Omar Infante less so. Seager and Rendon have been the best hitters in the group because they’ve hit for the most power, and given Betts’ size, his eventual power output is always going to be a question.

But Coco Crisp is kind of an interesting comparison, because like Betts, he’s not particularly reliant on the home run ball to create offensive value, but he’s also not a slap-hitting singles guy. He’s more similar in stature to Betts than Seager or Rendon, and based on physique, this seems to be a more realistic short-term power ceiling. And late-vintage Coco Crisp has quietly developed into a pretty solid hitter, posting a 116 wRC+ since the start of the 2012 season. Combined with his speed and defense, Crisp has been one of the game’s most underrated players, and a key reason for the A’s dominance over the last couple of years.

Of course, Crisp didn’t begin to control the strike zone to this degree until recently, in his mid-30s. Plate discipline is often referred to as an old player skill, as walk rate peaks in the second half of a player’s career. If Betts is already somewhat close to where Crisp is, but he’s there at 21, what does that mean for his long term future?

That’s a little less clear, to be honest. Using the filters on the leaderboards, I’ve created a list of young players who — in the last 30 years — controlled the strike zone while hitting enough power to avoid the slap-hitter label but not enough power to be a serious middle-of-the-order guy. At the top of the list, you see a name like Roberto Alomar and see the obvious potential in a guy who can handle the bat, hit for some power, play good defense, and steal a lot of bases. Dustin Pedroia and Barry Larkin are also reminders of how good these types of players can be, and that Betts doesn’t have to turn into a big time home run guy in order to be a star.

But there are a lot of guys on that list who peaked early as well. Maybe Jason Kendall and Russell Martin would have hit for more power later in their careers if they hadn’t been subjected to catching, but both had very similar offensive skillsets at a young age and were at their best early in their careers. Gregg Jeffries never really quite amounted to what he was thought of as a prospect. Denard Span has settled in as an average hitter, and is kind of a better defensive version of Shannon Stewart, who also is on the list. Edgardo Alfonso had a nice peak, but was washed up at age-29.

It’s not entirely clear that Betts’ skillset will follow the traditional peak-at-27 model. With an advanced approach at the plate and limits on his eventual power by his physique, Betts might be more likely to top out as a good player rather than a great one. That isn’t to say he couldn’t surpass expectations and turn into Roberto Alomar or Dustin Pedroia, but it seems more likely that he settles in to the mold currently filled by the likes of Crisp or Brett Gardner, with maybe a little more power than either one.

That’s certainly not a knock on his future value, as an improved version of Crsip or Gardner is something like a +4 WAR player on an annual basis. Even as an outfielder instead of a second baseman, Betts could make a significant impact on the Red Sox, and his skillset looks like one that could translate well in the short term. With Shane Victorino, the Red Sox saw last year just what an undersized outfielder who specializes in contact and line drives can do, and while Betts isn’t a Victorino clone, he could provide similar value going forward.

He might not have the kind of tantalizing upside of Xander Bogaerts or Gregory Polanco, but don’t be too surprised if Betts outplays them both the rest of the year. Both might eventually turn into better players as they grow into their power, but Betts present skillset is plenty good, and as long as he handles the outfield conversion well, he’ll be a valuable contributor for the Red Sox both in 2014 and beyond.