It’s easy to forget that St. Louis Cardinals minor league prospect Dylan Carlson entered the 2019 season as a relatively minor prospect. Per MLB.com, Carlson ranked just tenth in the Cardinals system, as he entered his first season with the AA Springfield Cardinals. But throughout the season, Carlson has emerged as, along with Nolan Gorman, the most exciting Cardinals hitting prospects since Oscar Taveras.

Promoting Nolan Gorman, who was still in high school sixteen months ago, to the Major Leagues might be a bridge too far for even the most aggressive prospect wanters. After all, Gorman will be a teenager until May 10 of next year and has never played at a level above high-A. But the notion of promoting Dylan Carlson, particularly when rosters expand to a maximum of 40 players in September, is far less fanciful. Many are aggressively campaigning for it, and while I will soon be a huge buzzkill and explain why this definitely fun thing shouldn’t happen, I do understand the argument.

Anybody who has followed Carlson’s 2019, even peripherally, should be able to understand the argument in favor of promoting Dylan Carlson as soon as possible. In 483 plate appearances at the AA level, Carlson hit 21 home runs, produced an AVG/OBP/SLG triple-slash of 281/364/518, and by wRC+, he was 43% above Texas League average–with the obvious caveat that the pitching he was facing was much worse, Carlson was the double-A equivalent to J.D. Martinez or Juan Soto. Upon his promotion to the AAA Memphis Redbirds, Carlson has been even better–through his first 49 plate appearances, Carlson produced a triple-slash of 455/510/773 (and a .567 batting average on balls in play, but while we’re talking about wildly unrealistic numbers, why ruin the fun?).

I should be clear about something, once again–Dylan Carlson in Major League Baseball this September, be it on September 1 or when the Memphis Redbirds season ends two days later (a playoff spot, while mathematically possible, is unlikely), would be so exciting. Watching him take MLB plate appearances would be more interesting than watching, well, any current St. Louis Cardinal take MLB plate appearances. And since he probably won’t get called up in September, it’ll be easy to proclaim how well Carlson would have done. But from a practical standpoint, there are several reasons that promoting Dylan Carlson doesn’t make much sense.

1. The Cardinals already have a bunch of outfielders. The St. Louis Cardinals have established a semi-regular outfield as of late featuring Marcell Ozuna, Harrison Bader, and Dexter Fowler. Ozuna and Fowler, the corner outfielders, have noticeably higher projected wOBA for the rest of 2019 than Carlson (Ozuna is at .340, Fowler is at .323, Carlson is at .305). In theory, you could work out some sort of platoon split, but Dexter Fowler, like Dylan Carlson, is a switch-hitter. Harrison Bader projects as a slightly worse offensive player, at .299, than Carlson, but since Carlson has only played sporadic center field, this incremental offensive upgrade would come at the cost of a Gold Glove-caliber center fielder. Fellow outfielders Tyler O’Neill and Jose Martinez, both on injury rehab assignments, also project for superior offense to Carlson. And beyond those five, and beyond the duo of infielders who have become semi-regular outfielders (please do not let anything I am saying in this post imply that I condone Yairo Munoz or Tommy Edman as outfielders), the Cardinals have five more outfielders on the 40-man roster–current MLB outfielder Lane Thomas and four more players with MLB experience–Randy Arozarena, Jose Adolis Garcia, Drew Robinson, and Justin Williams.
2. Hitting MLB pitching is really tough! A counterpoint to the volume of the Cardinals’ outfield depth is that only four of the the ten outfielders currently on the 40-man–Ozuna, O’Neill, Martinez, and Fowler–project to be better offensively, so the case can be made that Dylan Carlson would be better than, say, Lane Thomas. And while Carlson may have higher upside and he is certainly a more acclaimed prospect, there can be a bit of a learning curve for young hitters, even for extremely good ones. Mike Trout, the best hitter in baseball today and a player with a legitimate chance to be the greatest player in baseball history when all is said and done, was called up to the Majors for the first time in July 2011, and in 135 plate appearances that season, he was a below-average hitter, sporting a shockingly un-Trout-like 220/281/390 triple-slash and an 87 wRC+. Earlier this season, the best hitting prospect in years, Vladimir Guerrero Jr., was called up to the big leagues for the first time, and while he has since come around and become the offensive force we expected him to be, he matched Trout’s 87 wRC+ in his first month in the Majors, with a 222/300/411 line. And as high as expectations are for Dylan Carlson, they don’t touch the expectations prospect hounds had for Trout or Guerrero.
3. It could cost the Cardinals somebody they don’t want to lose. The Cardinals have 40 players on their 40-man roster, which means that a player would have to either be designated for assignment or moved to the team’s 60-day Injured List in order to accommodate Dylan Carlson. The only two currently-injured Cardinals now already on the 60-day IL are O’Neill and Martinez, who will be back and available sooner rather than later. So at that point, the Cardinals would be forced to expose somebody to waivers. And while the loss of Rangel Ravelo or Ramon Urias may not seem major, I’d still rather avoid losing them whenever possible. And there will be further 40-man considerations in the off-season: while pending free agents will drop off, Jordan Hicks and Brett Cecil must be re-activated (or cut, I guess), and then the Cardinals will have to worry about the Rule 5 Draft, during which veteran minor leaguers can be selected by other teams if they are not on the 40-man roster. Carlson will not be exposed to the Rule 5 draft no matter what happens the rest of the year, but such prospects as Elehuris Montero (currently #4 in the Cardinals system), Jake Woodford (#13), Conner Capel (#24), Max Schrock (#30), or unranked prospects such as Juan Yepez (who has raked at all three levels at which he has played in 2019) will need to be added to the 40-man. Maybe none of these aside from Montero, who will surely be protected, seem like big losses, but as with Ravelo or Urias, I’d rather not lose them.
4. Why start his service time clock? To be clear, the Cardinals should not manipulate Carlson’s service time, and I hope that with what Fernando Tatis Jr. and Pete Alonso were able to do without the Padres or Mets using technicalities to deprive them of an extra year of free agency, it sets a precedent across baseball that players who are good enough to play every day in the big leagues are able to do so. But how sure are we that Dylan Carlson would make the big league club out of Spring Training next year? He deserves a shot, but with the possible exception of Ozuna, the glut of outfielders on the 40-man will still be around next year. It’s one thing to assume Carlson is good enough to be among the 40 best players on the Cardinals–it’s another to assume he’s among the top 25.

Promoting Dylan Carlson would be delightful and exciting. But the uncertainty surrounding a 20 year-old with less than 100 plate appearances in AAA could make the process less fun.