We'll probably be awash in Andrew McCutchen rumors all offseason long, wondering if and when the Pirates might move him to Los Angeles or Washington or Seattle or wherever they may find a fit. But what if that's not the move we ought to be talking about? What if the right move is simply a few dozen feet to his left? Might the Pirates really be better off with McCutchen in right field?
We first heard rumors about this earlier in November, and on the surface, the fit is odd. Right field, after all, is generally where the strongest outfield arms end up, and McCutchen isn't particularly known for the strength of his throwing arm. Using the Statcast™ "competitive throws" metric, McCutchen's average of 85.8 mph was far lower than Starling Marte's 97 mph (the best in baseball), and slightly lower than Gregory Polanco's 86.6 mph.
Since Polanco was already playing right field (he'd be in left, with Marte in center in the proposed new configuration), and his arm isn't much stronger (though perhaps more accurate), perhaps that shows that the team wouldn't lose all that much from where it already stood in terms of arm strength in right field. Mostly, what it shows is that there's a lot more to picking outfield positions than throwing arms.
McCutchen, after all, compiled -28 Defensive Runs Saved, the lowest mark in baseball, and the second-worst season any outfielder has had since 2008. There's no way to talk around that and suggest that McCutchen had a good defensive season, but as we showed in September, there's also evidence that a well-intentioned positioning change may have backfired on him. While the Cubs movedDexter Fowler deeper to track down extra-base hits, helping him look better in the metrics, the Pirates pulled McCutchen in shallower, hoping to take advantage of the groundball (and short fly ball) tendencies of the Pittsburgh staff.
It didn't work, and Pirates manager Clint Hurdle said as much to MLB.com's Adam Berry in October:  
"As this staff played out, it didn't match up to the same analytics off the mound that we were looking to work with the defense," Hurdle said. "We have some thoughts moving forward on how to adjust."
So do we. With Statcast™, we're able to see the hang time of each batted ball, and we know how far away each fielder was from the ball's projected landing point. (It's a lot harder to catch a ball with a three second hang time when you're 70 feet away than 20 feet away, for example.) Using those two data points, we can come up with a pretty good "catch rate percentage," identifying how often across the Majors fielders could get to a batted ball with similar hang time and distance characteristics.
Got that? Let's use that data to look at the balls McCutchen caught that had catch rates between 25 percent and 75 percent. That is, let's take out for now the easiest 25 percent of batted balls, the ones that are usually turned into outs, and the hardest 25 percent, the ones that generally become hits. Let's look at the opportunity space in the middle that gives a fielder the chance to set himself apart from his peers. Notice anything interesting on McCutchen's chart? (The red dots are ball landing points, the blue dots are fielder starting position.)

That sure seems like a player who is far more comfortable going to his right, doesn't it? Just about every catch in the middle 50 percent of catch rate that McCutchen made was towards left field.

When you look at one of the good plays to right and watch the video, you can see that he does indeed make the play, but even then it doesn't feel graceful, as though he misjudged it at the last second and was able to compensate.

And, of course, there were the ones he couldn't come down with at all.

What about some other center fielders for comparison? Well, McCutchen played 1,318 innings in center in 2016, and the two with the nearest amount of playing time were Philadelphia's Odúbel Herrera, who had 1,301 innings and was considered an above-average fielder (+6 DRS) and Baltimore's Adam Jones, who had 1,300 innings and came in at -10 DRS -- perhaps in part because he, like McCutchen, played an especially shallow center field.
On those same plays in the "middle 50 percent," Herrera showed an ability to go to both sides, unsurprisingly.

Jones, meanwhile, got to fewer of those balls than Herrera, but if he had any issue, it was in coming in to catch those balls -- which perhaps makes sense, given his reputation as a shallow fielder who can run back.

So does that mean that the 25-75 percent balls that McCutchen didn't catch landed only to his left (i.e., towards right field)? Not exactly. Let's show you what that looks like with the hits (green) and catches (red) both displayed, and while that gets a little busy, you can see that the potentially catchable balls he couldn't get to were in all directions. That makes sense, too, because while it's more than fair to say that McCutchen was unfairly dinged by DRS in 2016, he still seemed to have trouble getting to some catchable balls.

What this looks like isn't that McCutchen only misses balls to his left, but moreso that he's only making very good plays on balls to his right. If this first crack at the data -- and yes, we're aware that it's a small sample and that we're all new to using it in this way -- tells us anything, it's that maybe the idea of McCutchen in right makes sense. In the year of data we're looking at, he was able to make some good plays going to his right, and rarely ever did so going to his left. You imagine him hugging the foul line in right field, minimizing that issue, and being free to roam back towards center. You can see him taking the lessons of 2016 and playing deeper, and you can see the numbers looking better already.
Sure, McCutchen's arm wouldn't be a great fit for right, but that may matter less than you think, because PNC Park's left-field power alley is so big (420 to the deepest part) compared to right (320 down the line, 375 in the power alley) that unlike many other fields, it's a lot harder to play left than right. That's a big part of why Marte, a fantastic defender, has stayed there. Either way, the average National League team allowed 73 singles to center with a man on first (i.e., potential first-to-third opportunities), and 80 to right. It's just not that big of a difference. 
After all, a strong outfield arm is nice. Being able to prevent extra-base hits, well, that's far better. If the Pirates do want to shift McCutchen over, they may be on to something.