Yesterday, I wrote about the Nationals’ upcoming decision in the wake of the Adam Eaton injury, talking about the pros and cons of sticking with an inferior option like Michael Taylor or making a big splash for a rental like Lorenzo Cain. In both the comments of the post and at the Pitch Talks show in D.C. last night, a number of people questioned why I focused solely on the potential acquisition of a CF, and didn’t talk about the possibility of acquiring a shortstop and shifting Trea Turner to center field as they did a year ago.

The idea seems to be fairly popular, and would expand the pool of players the Nationals could look at, putting them in a better position to upgrade without having to pay an extreme price due to the lack of quality center field options. But here’s the primary reason I didn’t devote any words to the idea in yesterday’s piece.

In theory, if Taylor doesn’t pan out, Harper could slide over to center field, where he spent most of his rookie season. Alternatively, Turner — who converted to center last year before returning to his native shortstop this season — could head back to the outfield. For the record, Baker doesn’t seem terribly interested in either of those contingency plans. “No,” said the Nats skipper dismissively when asked on Saturday morning if he was open to the idea of Harper or Turner taking over in center field. “Leave my team alone.”

While Baker isn’t necessarily the final word on the matter, and he could always change his mind, this isn’t the kind of vague non-answer a manager often gives to indicate that they’re considering a number of options and just haven’t decided which way they’re going yet. The definitive nature of his answer suggests that this isn’t something that Baker is interested in doing, and if the manager doesn’t want to move his starting shortstop to center field, it’s difficult to see the Nationals doing it, even if the front office believed it was the best idea. That’s probably not a fight anyone wants to start on a first place team.

But let’s put Baker’s resistance aside; would acquiring a shortstop and shifting Turner to center field be a better option than simply acquiring a center fielder to begin with?

To make the idea worth pursuing, there’s a three-part criteria that would have to be met.

1. There’s likely to be a shortstop available to acquire who would represent a better return for the price paid than the best option among center fielders.

2. The difference between the acquirable SS and CF is larger than the expected decline in value you’d get from Turner transitioning positions in-season.

3. There would be minimal long-term impact on Turner’s development as a shortstop by having him again spend the bulk of the season playing the outfield.

Let’s tackle those in order.

While we identified Lorenzo Cain as a quality center fielder who is probably getting traded this summer, there doesn’t appear to be a similar caliber of rent-a-shortstop. The best SS on a non-contender is Zack Cozart, and while he’s off to a strong start, his career 83 wRC+ is well short of Cain’s 105 mark, and by career WAR, Cozart’s +10.9 mark is just over half of Cain’s +20.2 total.

Of course, career totals aren’t always indicative of a player’s future production, and the wRC+ gap is smaller when we look at the ZIPS/Steamer rest-of-season projections, where Cain’s edge drops to 98 to 87. Cozart’s tapped into some power the last few years that he didn’t have previously, and Cain’s power has mostly regressed since his one spike up in 2015, so perhaps the offensive edge Cain has displayed is smaller than the career numbers suggest.

That said, Cain is the better player. Cozart’s a good defensive shortstop with perhaps an improving bat, but Cain’s an elite defensive CF who still hits better than even improved-Cozart. Acquiring Cozart instead of Cain would result in a less-impactful upgrade for the Nationals.

Of course, that could be a decent alternative if the cost differences are dramatic, but I’m not sure that we should expect Cozart’s cost relative to his production to be significantly different than Cain’s. While expanding the pool to include shortstops would give the Nationals more players to look at, they’d also be expanding the pool of teams they’d be competing against for those players, and shortstop isn’t any deeper in likely trade candidates than CF is.

Besides Cozart, the other decent shortstops that could be available this summer include Troy Tulowitzki and Alcides Escobar. Tulo is 32, expensive, and not hitting well. Escobar is 30, cheap, and not hitting at all. They are not particularly attractive trade targets at the moment, and while they could up their stock before the summer comes along, I don’t think having either Tulo or Escobar out there is going to significantly weaken the market for Cozart. There’s not a big imbalance of supply and demand at the shortstop market that would cause the Reds to have to take peanuts for Cozart, at least that I can tell.

So right off the bat, the criteria kind of falls apart. Cozart would cost less to acquire than Cain because he’s a less impactful upgrade, but I don’t know if that’s a great pitch to the Nationals, really. You’d think if they were going to move Turner around again, it would be for a guy they couldn’t resist adding, a player who would really move the needle on their championship odds. Zack Cozart isn’t that guy. He’s a nice player, but I don’t think he significantly moves the needle on the team’s chances of advancing deep in the postseason.

And even if the Reds were willing to trade Cozart for a fraction of what the Royals wanted for Cain, the second part of the criteria would probably scuttle the idea as well. While Turner is certainly fast and looks like he could be a good center fielder long-term, the early evidence we have from last year doesn’t suggest that it was an easy transition for him, and he is probably a worse defender in CF now than he is at SS.

While you don’t want to draw too many conclusions from a half season of UZR or DRS, we do have some Statcast data on Turner from his time in CF last year, and there’s nothing here that makes you think he was a particularly great outfielder as a rookie. According to the Catch Probability metric that MLB has released, Turner looked like a fairly pedestrian outfielder last year.

Turner’s Catch Probabilities Turner Opportunities % Made League Average Five Star 12 0% 8% Four Star 5 80% 42% Three Star 4 75% 68% Two Star 5 100% 84% One Star 16 94% 93%

With 12 five-star opportunities, the league averages would suggest that maybe he could have gotten to one of those, but he went 0 for 12. He did make an extra four-star and two-star play relative to the overall average, but these averages are for all outfielders, and center fielders being the best defenders of that population, they should be making plays above the overall baseline.

This isn’t to criticize Turner for not being a great CF after coming up as a minor league SS; it’s just an acknowledgment that learning a new position in the big leagues is hard. Tracking balls is a skill. Learning how to read the slice on line drives isn’t something that just comes naturally. Getting confident enough in your reads to make an immediate first step comes from experience. If Turner had spent most of spring training working on his outfield defense, maybe this would be a different story, but right now, his athleticism mostly covers for his lack of training at the position. Sticking him in center field is probably taking away some of his current defensive value.

So if you trade for an SS instead of a CF, you’re probably devaluing Turner’s performance over the remainder of the season as well. It might not be a dramatic downgrade, as he’s not Andrelton Simmons at shortstop or anything, but there’s likely to be some lost value with Turner shifting to a new position mid-season once again. And that’s without accounting for the long-term consequences of taking away his development time at shortstop for the second year in a row. While this is obviously much more difficult to quantify, it is hard to imagine it’s good for Turner’s chances of sticking at shortstop to again shift to the outfield and lose the time he would otherwise get developing as the team’s long-term SS.

While I do see the appeal of potentially expanding the pool of potential players to be acquired, I’m not sure I see the upside in moving Turner to CF again. Cozart would be cheaper than Cain mostly because he’s worse, and I don’t know that moving one of the team’s best young players to accommodate a lesser upgrade is really beneficial to the organization, either this year or in the future.

To me, it still feels like the Nationals will effectively have to choose just how heavily they want to push in on 2017, and whether they’re willing to pay a real price to maximize their chances of winning this October. Going half way, and moving Turner again to accommodate a less substantial upgrade that doesn’t move the needle that much, doesn’t seem that appealing an option to me.