There are a few teams in baseball that just don’t trade with each other, at least not in any meaningful way. The Cubs and White Sox don’t send impact players to their crosstown rivals. The Dodgers and Giants would rather do anything else besides strike a significant trade that might help the other, to the point where you only have to go back four trades between the two franchises before you find a deal that involved Jackie Robinson. Yes, that Jackie Robinson; the deal was voided when Robinson refused to report to the Giants.

Less well known, the Cardinals and Royals also mostly just ignore each other in trade talks. They’ve made four trades together in the last 21 years, involving immortal players like Jose Martinez (twice), Tony Cruz, Jamie Romak, Victor Marte, and Jason Ryan. Back in December of 1995, the Cardinals helped facilitate a three-way trade in which the Royals got Mike Remlinger from the Reds, a move so essential that Remlinger actually never pitched for Kansas City, as he was claimed back on waivers by the Reds before the 1996 season started.

Realistically, the last significant trade between the two franchises was in February of 1993, when St. Louis sent Felix Jose to Kansas City for Gregg Jefferies. Both players had been roughly average players the year before, but Jefferies turned in a +5.4 WAR season in 1993 for St. Louis, while Jose put up a -0.9 WAR season in KC. The Royals apparently decided the Cardinals were not to be trusted after that, and we’ve now gone 23 years without a significant move between the two organizations.

But in reading Jeff’s post yesterday, and thinking about what the Royals could do this winter besides just sit around and hope things break their way, I started to think that Dayton Moore and John Mozeliak should thaw the ice. It’s time for the Royals and Cardinals to make an interesting trade again.

Now, to be clear, this isn’t exactly a groundbreaking idea. The Cardinals have made it clear that they want to upgrade their outfield defense, and they’d like to do that by acquiring an athletic center fielder. The Royals, for all their flaws, have more athletic center fielders than they know what to do with. Jeff speculated last week about Jarrod Dyson as a fit for St. Louis, and yesterday, there were a bunch of rumors about potential fits between the two teams.

#Royals have talked to #STLCards about dealing Cain/Davis for Wang and package of prospects. #MLB — John Perrotto (@JPerrotto) December 5, 2016

“Wang,” in that case, is Kolten Wong. Unfortunate typo aside, the idea of the Royals sending Lorenzo Cain and Wade Davis to St. Louis is fascinating, even if the prospects in question would have to be pretty good to merit the acquisition of a couple All-Stars at below-market prices. That would be a blockbuster trade, the sort of deal these teams don’t ever make. So let’s think about what deal could make sense for both sides.

From the Cardinals’ standpoint, it’s easier. Cain solves their center-field problem! A healthy Wade Davis would be really good! Kolten Wong is easily replaced by Jedd Gyorko, and if they needed another middle infielder, they have Matt Carpenter playing first base, so they have more than enough depth there. “Prospects” is vague enough that it could mean anything, but the idea of Wong and some other stuff for two significant pieces makes it seem like an easy yes from St. Louis’ perspective, unless “prospects” means Alex Reyes or something.

But if you’re the Royals, there’s no real point to that deal. As Jeff noted yesterday, 2017 is the end of the line for this group, and if they don’t win this year, they’re not winning again for a while. The team’s best players are headed for free agency, the farm system isn’t good, and as a mid-market club, they can’t spend their way out of their upcoming talent problem. Turning 2017 value into some long-term value isn’t really worth it unless you’re blowing it up and completely rebuilding, because then all you’re doing is making it more likely that the team’s last run together comes up short, and there still won’t be enough talent to make the future years worth punting the one last chance they have to make another run with this group.

So if the Cardinals and Royals are going to make a trade, it’s not going to be a current-for-future swap that makes St. Louis a lot better now and Kansas City better in the future. If the Royals are moving Cain and Davis now, instead of waiting until the deadline when both have had a chance to prove they’re healthy again, they have to get pieces in return that don’t make them appreciably worse in 2016, while also providing value beyond just the 2017 season.

Wong can fit that bill, to some degree, as the Royals could use a better second baseman. But Wong is only an upgrade for the Royals because the Royals’ current second basemen project to be replacement level; he isn’t exactly a great player. He has a career wRC+ of 87, and while he’s fine defensively and runs the bases well enough, the overall package is something like league average, and that’s if you ignore the fact that he went the wrong way in 2016.

A league average 26-year-old signed for four years and $24 million is a nice thing to have, but this isn’t a guy who is going to turn around your franchise or anything; he’s a cheaper-than-market-rate role player who should probably be platooned. For the Royals to offset the value lost by trading Cain and Davis, they’d have to get some significant big league pieces elsewhere.

And realistically, I don’t think the Cardinals need Davis enough to be the team to pay the price that should make the Royals trade their closer. St. Louis already has an elite reliever in Seung Hwan Oh, a couple of very good lefty setup guys in Brett Cecil and Kevin Siegrist, and the wild cards that Trevor Rosenthal and Michael Wacha now represent. If Rosenthal’s September is a sign that he fixed whatever was wrong last year, then the Cardinals probably already have the best bullpen in the National League, and Davis would be a bit of overkill. There are only so many high-leverage innings to go around, even with the game moving towards more relief innings.

If I’m Kansas City, I’d rather send Davis to a team like the Cubs or Dodgers, a team that doesn’t really have a ninth-inning guy with whom they’re currently comfortable, and would pay a bigger premium for the upgrade they’d get in their bullpen. The idea of swapping Davis for Jorge Soler and something else is more interesting to me, for instance. Soler is, in some ways, the outfield version of Wong at this point; a mid-20s guy who hasn’t shown he can be an above-average regular yet, but has a long-term deal at cheap prices that makes him somewhat useful even if he just is what he is. Except Soler still has mythical upside: if he figures out how to hit like people think he could hit, his value would skyrocket.

So, let’s just wildly speculate a bit. Let’s just say the Royals did some kind of Wade Davis-to-Chicago deal that landed them Soler and, say, Jeimer Candelario — the most blocked prospect in the history of prospects, given that he’s behind Kris Bryant on the Cubs depth chart — as a potential replacement for Mike Moustakas. Candelario would give them some needed infield depth even if he doesn’t fit their 2017 roster, and if Soler turns into a solid right fielder, the Royals aren’t that much worse off in the short term.

Especially because, if you add Soler to the outfield mix, it’s easier to trade Cain or Jarrod Dyson without experiencing as large a downgrade. Paulo Orlando is still around as a nice-enough fourth outfielder, but there wouldn’t be much depth behind a starting group of Gordon-Cain/Dyson-Orlando, and if any of those guys get hurt — which they’re known to do — then the 2017 Royals could be in a lot of trouble. And if you’re going to put yourself in a position where an injury to an injury-prone guy ruins your season, well, you might as well just blow it up then.

But now, with Soler around, you can more easily handle a loss of Cain or Dyson, and can do a deal with St. Louis. Let’s say the Cardinals want Cain, the guy who has shown he can play every day when healthy; Wong can be part of that deal, but you don’t make that move one for one, even with the extra control years. But the Cardinals also have Matt Adams, who’s without a job in St. Louis and could serve as a serviceable DH for the Royals. Adams isn’t anything special, but a +1 WAR DH got $33 million from Toronto and a +1 WAR first baseman is asking $80 million from the Orioles, so the market still overpays for this skill set, and KC would get two years of cheap power at a position where they also have a total zero right now.

Wong and Adams for Cain sounds like a terrible deal for the Royals, I know. It’s an All-Star center fielder for two guys who can’t crack a good team’s lineup. It’s a star for bit parts, and people hate those kinds of trades. But the Royals have serious depth problems, and Wong and Adams would represent real upgrades at positions where the team can’t expect to get any real production right now.

And if you’ve looked around the free-agent market lately, you’ve seen that even reasonably useful role players who could fill these spots aren’t cheap anymore. Matt Joyce, Steve Pearce, and Sean Rodriguez all got basically $12 million on two-year deals to be part-time players on the wrong side of 30, and a guy who looks like he can play not horribly even close to an everyday basis now costs somewhere between $13 million (Holliday) and $33 million (Morales). The Royals can’t just go sign cheap veterans to provide real value at second base and DH; prices for those kinds of players aren’t anywhere near zero, and the Royals are pretty close to being out of money to spend.

So, while it’s not a sexy return, this is the type of deal that could keep the Royals decent in 2017 while giving them some long-term value. Yeah, they could get more upside if they went for guys without any present value, but the Royals shouldn’t be throwing in the towel on 2017 yet, or they should be throwing it in entirely and just trading all the walk-year guys; going halfway isn’t a good plan.

If the Royals made these two trades and then reinvested even half of the $15 million in payroll, they may have enough to bring in some free agent pitcher to give them rotation depth. And with that guy, this version of the 2017 Royals could be just as good as the current one, only they’d have turned a couple of one-year guys into three multi-year younger players, plus a prospect who could replace another one-year guy if need be, plus whatever depth starter they could add to supplement the rotation. This kind of deal could make the 2018 Royals way more interesting without doing much damage to the 2017 Royals.

It’s never sexy turning a couple of All-Stars into three mediocre players who haven’t lived up to their potential yet, but Soler, Wong, and Adams could provide enough short-term value to let the Royals still think about contending next year while also building for the future. And if you throw enough darts like that, perhaps one of them has their breakout year, and all of the sudden you’ve got a core player to build around. These are the kinds of trades a team in the Royals’ position should be thinking about making.

And though it wouldn’t be as big of an upgrade as the “Wong and some stuff for Cain and Davis” headline, this is still the sort of trade that would convert a couple of guys the Cardinals don’t need for a guy they could really use. It’s a move that could legitimately help both Missouri teams, and might erase the ghosts of the Felix Jose/Gregg Jefferies swap. I wouldn’t expect the Cardinals and Royals to become regular trade partners, but this year, it looks like the two might be incentivized to make a deal.