In both the 2017-18 and 2018-19 off-seasons, the marquee move for the St. Louis Cardinals followed a familiar pattern–the Cardinals acquired a premium, middle-of-the-order offensive threat with dwindling remaining years of club control in exchange for a handful of decent, already MLB-caliber young players and prospects. In December 2017, the Cardinals traded four prospects, two of whom had MLB experience, to the Miami Marlins for Marcell Ozuna. In December 2018, the Cardinals traded effectively four prospects (three plus a draft pick), two of whom had MLB experience, to the Arizona Diamondbacks for Paul Goldschmidt.

In each case, the Cardinals acquired a player who fit the description of what the team was hoping to acquire during the off-season, and yet the method by which the Cardinals acquired each player was a tad unsatisfying. For both Ozuna and Goldschmidt, their team-favorable contract situations made them precious commodities, hence giving up players of real value to acquire them. Had the Cardinals instead, say, signed Josh Donaldson last off-season rather than trading for Paul Goldschmidt, the Cardinals would have acquired a comparable offensive player (Donaldson was better in 2019, but at the time, this wasn’t particularly the expectation), improved their defense by slotting a superior fielder into the higher leverage defensive position, and most obviously, not lost Luke Weaver and Carson Kelly in the process.

To be clear, I liked the Marcell Ozuna trade and was fine with the Paul Goldschmidt trade, but in each case, it felt like a better move could have been made. The Cardinals could have signed J.D. Martinez or Lorenzo Cain (this feels like a Retrospect Hall of Fame take, as both of these players were fantastic in 2018, but I can’t help that they were the top outfielders on the market) in 2017-18 and saved their prospects. This is why I’m weary of categorizing trades for top-end talent as analogous to signing top-end free agents.

But this off-season, in addition to a somewhat top-heavy free agent class, there are potentially curve-breaking players available via trade. Chicago Cubs third baseman Kris Bryant, allegedly available via trade, would be a tremendous addition for many teams, but the Cardinals already have committed $39 million over the next two seasons to a third baseman in Matt Carpenter, and given the public backlash the Cubs will face for trading Bryant to any team, adding further fuel to the fire by trading him to the team’s biggest rival would likely require the Cardinals to offer a substantially stronger package than any other team. Cleveland Indians shortstop Francisco Lindor is tremendously valuable, the consensus best shortstop in baseball, but the Cardinals already have a top ten-ish shortstop of their own in Paul DeJong. This isn’t to say that the Cardinals wouldn’t accommodate Lindor, but he marks less of an improvement for the Cardinals than he would, say, for the Atlanta Braves or New York Yankees.

But in Boston Red Sox right fielder Mookie Betts, there is a player on the trade market who fills not only a need, but arguably the need, for the Cardinals. He is a player who does not have anywhere close to a comparable alternative on the free agent. He is, with the extremely unrealistic exception of Mike Trout, the single player in Major League Baseball who could most improve the St. Louis Cardinals for the 2020 season. If the St. Louis Cardinals aren’t placing calls to the Red Sox and inquiring about the availability and cost of Mookie Betts, they aren’t doing their job.

For those who do not follow the Boston Red Sox, or by extension the American League, very closely, here is a quick primer on Markus Lynn “Mookie” Betts, the 27 year-old right fielder who is projected by the Steamer projection system to be the second-best player in Major League Baseball next season, behind only Mike Trout. Since 2015, Betts’s first full season in MLB, he has trailed only Trout in Wins Above Replacement, and despite not even so much as making his debut until midway through 2014, he was the decade’s 13th best position player by FanGraphs WAR; you’d have to scroll all the way down to 29th to find a player on the list with fewer plate appearances than Betts. In the long history of the Boston Red Sox, only 13 players have been more valuable by Baseball Reference WAR–if Betts remains in Boston and performs up to his projections in 2020, he would pass Jim Rice, a career-long Red Sox player who is in the Hall of Fame.

There isn’t really a great comparison for Mookie Betts–the closest thing to Betts in recent memory was Atlanta Braves-era Jason Heyward, a player the Cardinals also acquired for his final season pre-free agency. Like Heyward, Betts is a defensive stalwart in right field who also provides solid offense. But this doesn’t properly convey the scale of Betts’s greatness–Betts is already a more valuable player by bWAR or fWAR than Heyward has been for his entire career, much less through the 2014 season. As great as Heyward was in right field, saving 54.1 defensive runs over 5539 innings in his first five MLB seasons, Betts has saved 69.0 defensive runs over 5075 1/3 innings. While Heyward did play some in center field, Betts has proven to be not only competent but adept at the position (the Red Sox have an elite defensive center fielder in Jackie Bradley Jr.) and has even played second base as recently as 2018 (he was rumored to have been considered to play the position for DH-less games during the 2018 World Series).

But what really separates Betts from Heyward is that while Heyward had a decent bat, with a wRC+ of 117, Betts’s 2019 wRC+ of 135 matched his career mark to this point. Betts was tied for the 11th most valuable offensive player in baseball last season with Peter Alonso, who hit 53 home runs. For context, a 117 wRC+ put Heyward on par with the career offensive productivity of Andre Dawson and Carlton Fisk, really good Hall of Fame players. A 135 wRC+ matches that of Joe Morgan and exceeds that of Al Kaline and George Brett, inner-circle, first-ballot Hall of Famers. Through the age of 26 (Betts turned 27 during the postseason), is one of the thirty greatest position players in the history of Major League Baseball by fWAR, and here is a complete list of the players in the last half-century who were better: Mike Trout, Alex Rodriguez, Ken Griffey Jr., Albert Pujols, Rickey Henderson, Andruw Jones, Barry Bonds, Cal Ripken Jr. Oh, and before I forget–Mookie Betts is also a crazily efficient base stealer, swiping 126 bags at an 83.4% rate, and over the last half-decade, only Billy Hamilton has been a more valuable baserunner by the FanGraphs measurement Baserunning Runs.

There literally isn’t a single team in baseball that wouldn’t be made more valuable by the addition of Mookie Betts–frankly, the idea that a team that should once again contend for a postseason berth in the Boston Red Sox is trying to rid themselves of their best player is distressing in a macro baseball sense. But from a Cardinals fan perspective, of course I want my team to be the one to take advantage of this absurdity.

In 2019, the Cardinals finished in 18th in baseball in fWAR among outfielders and 10th among baseball’s ten playoff teams. In right field, even with Dexter Fowler dramatically improved from his horrendous 2018, the Cardinals ranked just 20th–only the Braves and the Oakland Athletics fared worse among playoff teams. This is a Cardinals team that started Tommy Edman, a utility infielder rookie, at right field in six of its nine postseason games in 2019. And this is a free agent outfield class that is headlined by Marcell Ozuna, a member of that mediocre outfield corps. The Cardinals would still be entering 2020 with a suspect outfield group even if they were to sign literally the best outfielder on the market.

Mookie Betts would provide not only a reliable right fielder for the Cardinals, but also a viable center field option if Harrison Bader’s offensive struggles continue into 2020. While the Cardinals have several intriguing young outfielders who have flashed star, or at least reliable, potential (Bader, Tyler O’Neill, Lane Thomas, Randy Arozarena, eventually Dylan Carlson), Betts already is that guy, and solidifying one outfield spot means relying on the youngsters to fill fewer spots.

Of course, acquiring Betts would come with a whole host of new questions. Here are the answers to those questions.

1. What do you do with Dexter Fowler, who is still under contract for two more seasons? You let him compete for a starting position in the outfield. Even with Betts, he might still be one of your three best options in the outfield–Fowler was, after all, an above-average hitter in 2019, and by Steamer projections, he is part of a cluster on the WAR leaderboard with Bader and O’Neill. And if Fowler is relegated to bench duty, well, that’s fine too. When you sign a guy in his thirties to a five-year contract at “be maybe a little bit above average” rates, him becoming a decent rotational outfielder by his fourth year is hardly a disastrous outcome.
2. Do you try to re-sign Mookie Betts to a long-term extension? Of course you do. If you have one of the five best players in baseball on your team, the answer is always yes.
3. What are the odds he actually signs an extension with the Cardinals? Low. Before he reaches free agency, I’d say nearly zero. Once he reaches free agency, probably still single digits, and even if he does re-sign, it’ll cost a small fortune. But that’s not why the Cardinals should acquire Mookie Betts–it’s for 2020. The time to strike is now for the Cardinals. The Cubs are apparently trying to sell. The Milwaukee Brewers are potentially losing two of their better position players, Yasmani Grandal and Mike Moustakas, in free agency. The Cincinnati Reds are improving and may look to make a big splash this off-season, but a Cardinals team that is functionally similar to last season’s but with Mookie Betts instead of Marcell Ozuna is absolutely the division favorite.

The important question here is cost–as in, how much will the Red Sox demand for Mookie Betts? And what types of players are they hoping to acquire? While Betts would be the best player on the Cardinals for 2020, I wouldn’t trade, say, Jack Flaherty straight-up for him, as Flaherty has four more seasons until he reaches free agency, and I expect Flaherty to be more valuable for the next four seasons than I expect Betts to be for the next one. Jon Heyman has suggested that, given Betts’s 2020 expected salary of about $28 million (a relative bargain for a player so talented, but not nothing) and pending free agency, he does not expect the right fielder to command a super hefty haul of prospects. It is entirely within the realm of possibility that the Cardinals could acquire Mookie Betts without trading Dylan Carlson nor Nolan Gorman. Looking at the rest of the top Cardinals prospects, I see a list of prospects I like but not “wouldn’t give up for Mookie Betts without blinking” like. The next three names up are Andrew Knizner, Elehuris Montero, and Zack Thompson. A catcher who hasn’t looked especially strong at the MLB level, a third baseman with a 52 wRC+ in AA last season, and a pitcher whose minor league track record is too small to draw particularly strong conclusions.

Speculating on how much a Mookie Betts would cost in a trade is a fool’s errand. I do not, for instance, believe that the fan who suggested to a local sports radio show a cost of Montero, Jose Martinez, and Austin Gomber is even in the correct stratosphere of what Betts would cost. However, the uncertainty around what Mookie Betts could command is further evidence that the Cardinals ought to shoot their shot. Players this good don’t become available too often. I won’t be outraged if the Cardinals don’t acquire Mookie Betts–I still believe the most likely outcome is that he remains in Boston for 2020–but he makes too much sense for the Cardinals to not at least try.