In 2017, the Arizona Diamondbacks won 93 games and made it to the NLDS. In 2018, the Diamondbacks weren’t quite as successful, but they did still finish over .500 and actually finished with a more positive run differential than the Colorado Rockies, who made it to the NLDS and finished the regular season proper with as many wins as the Los Angeles Dodgers. In most eras, this would demonstrate that the Diamondbacks, while not NL West favorites, are a few good breaks away from being able to sneak into the playoffs. In 2018, that apparently means it’s time to tear the whole thing down.

On an aesthetic level, let me be clear–I hate this. Even if the Diamondbacks were to lose Patrick Corbin and A.J. Pollock in free agency, they have the financial capacity to sign close-ish replacements for both and they have enough talent to make a run at October. Instead, not only are the departures of these two a foregone conclusion, but two of the team’s three best players in 2018 (with Corbin being the other) are firmly on the trade block–starting pitcher Zack Greinke and first baseman Paul Goldschmidt. And if these players are available, as much as it annoys me that they are, the Cardinals should be in on them.

These two players are quite different as potential acquisitions for reasons beyond just their positionality–Zack Greinke is 35 years old and is owed $34.4 million per season for the remaining three years of his contract. He remains an effective starter, even if he is ever-so-slightly past his peak, and while $34.4 million for a pitcher of Greinke’s caliber isn’t a complete disaster, this would wind up being a salary dump for the Diamondbacks. Unless they retain a significant portion of the contract, they wouldn’t receive a significant prospect in return.

Paul Goldschmidt, however, is 31 years old, and he requires far less financial commitment–he will make $14.5 million in 2019 and then become a free agent. In 2018, Goldschmidt had a typical Paul Goldschmidt season–he hit 33 home runs, mustering a triple-slash of .290/.389/.533. Goldschmidt’s 145 wRC+, of Major League Baseball’s 145 qualified hitters, ranked 8th. He almost certainly had the best offensive season in 2018 of players who will be available this off-season.

The biggest “pro” to signing Paul Goldschmidt almost goes without saying–he’s a really good hitter. And a surprisingly good base runner, at that–most people wouldn’t associate a 6’3, 225 pound first baseman with the kind of wheels required for 124 career steals, including 32 in 2016, but Paul Goldschmidt has proven to be a very complete offensive player. His defense is less a part of his game–all of his MLB games (and all but one of his MiLB games) have come at first base–but he’s been basically average in the field. While his defensive metrics were down a little bit in 2018, there isn’t really much reason to believe he would be a disaster in the field in 2019.

Still, adding Paul Goldschmidt would hurt the overall defense of the Cardinals because of the presumed subsequent move–sliding Matt Carpenter over to third base. Carpenter and Goldschmidt are probably roughly analogous at first base–neither is the rare first baseman who is a real difference-maker in the field, neither is an abject disaster, both are there for their bats. But Carpenter’s range and particularly his arm have declined in recent years. While his defensive shortcomings have often been exaggerated for effect–putting Carpenter at third isn’t in the same stratosphere as, say, when the Atlanta Braves played Freddie Freeman at third base to accommodate Matt Adams for some reason–there is little question that Jedd Gyorko (30) is presently a superior fielder at the hot corner than Matt Carpenter (33).

To be clear, this move would still make the Cardinals a better team. If you have a chance to start Paul Goldschmidt and Matt Carpenter as your corner infielders, you accept the decline in defense. That is a duo that is up there with the Chicago Cubs, Atlanta Braves, and (weird as it feels to say out loud) the Cincinnati Reds as the best in baseball at the plate.

Paul Goldschmidt is the kind of player who is good enough that you build the rest of your team around him, rather than requiring an exact fit to add him, but this does make the case of Goldschmidt at least marginally different from that of Jason Heyward, the most recent and notable example of the Cardinals acquiring an established star as a one-year rental. With Heyward, the Cardinals had a pressing need for a right fielder–their starter on Opening Day of the previous season had been traded, their top prospect at the position had died, and the incumbent was a very unproven Randal Grichuk. Goldschmidt would be essentially replacing Jedd Gyorko (who may well be traded if such a move were to happen), a slightly better than league average player in 2018, his worst season in St. Louis. An upgrade, to be sure, but not as overwhelming of one.

Although it was not a one-for-one trade, the Cliff’s Notes version of the Jason Heyward trade was that the Cardinals sent Shelby Miller to the Atlanta Braves. Miller, an acclaimed pitching prospect, had an impressive rookie campaign but had a concerning sophomore season. The Cardinals have a somewhat lesser version of Fall 2014 Shelby Miller on the team currently–Luke Weaver. Weaver wasn’t quite as acclaimed of a prospect, he didn’t have as sustained of success as a rookie (though on a rate basis, by defense-independent metrics, he was arguably better), and he’s a year older, but he is in a similar mold.

Mentioning Shelby Miller to the Diamondbacks might not be a savvy move–their acquisition of the ex-Cardinal from the Braves has been a disaster, with Ender Inciarte and Dansby Swanson starting for the NL East champions last season. But a pitcher with Luke Weaver’s upside and cost control–he is not even eligible for salary arbitration until after the 2020 season–could have a ton of value for a rebuilding team. While I’m a bit wary of the Cardinals’ tendency to sell low on young players, and while I still think Weaver can rebound and become a viable starter, I’m less certain than I was a year ago. I would make a Weaver for Goldschmidt trade.

This is blind speculation, but I suspect Luke Weaver alone wouldn’t be enough. Unlike Heyward, whose value largely came from his defense, Goldschmidt has the more obvious type of value that arguably makes him more expensive. Also, unlike Heyward, Goldschmidt is one of the greatest players in the history of his franchise (Wins Above Replacement of both the Baseball Reference and FanGraphs variety have him behind only Randy Johnson), and there are cosmetic reasons that trading the face of a franchise is more difficult than trading merely a really good baseball player.

The question becomes what it would take. I’d give up more than Luke Weaver, but I wouldn’t give up that much more. The negatives of Goldschmidt are outweighed by the positives, but they are still very much there. The Cardinals would still be trading for one year of a player on the wrong side of thirty, a player who remains excellent but has shown some signs of incremental decline (for several seasons, Goldschmidt’s walk rate has declined while his strikeout rate has increased). The Cardinalns would probably still be in a position to recoup draft pick compensation if (given Matt Carpenter’s 2020 team option and unlikelihood of being able to fake it at third base for a second year, probably when) Goldschmidt walks in free agency, but that a pick would eventually sniff the big leagues is hardly a certainty.

I’m not sure if Paul Goldschmidt fulfills the desire of countless Cardinals fans for A Star In The Middle Of The Lineup (or of those who demand a lefty bat, since apparently a lefty didn’t just hit 36 home runs last year), but he improves the team, and that’s really what matters. But there are inherent limits to what impact Goldschmidt can have, and mortgaging too much of the future for one run at a loaded NL Central may be short-sighted.