Ahead of tonight's game with the Diamondbacks, the Cardinals made a fairly surprising move, sending down Aledmys Diaz and calling up Alex Mejia. The callup seems much more to do with Diaz and Paul DeJong than Mejia, who hasn't really hit well in five minor league seasons. Diaz hasn't hit well this season with a .260/.293/.396 line that is roughly 20% below the average hitter, although that isn't too far off from the average shortstop.
It is worth noting that if Diaz spends more than a couple weeks in the minors, the team would gain an extra year of control before free agency. While a quick move is relatively harmless for Diaz’s future earnings now, it is likely something both player and team are playing close attention to over the next few weeks.
Diaz is coming off a great season for the Cardinals and that season was rewarded by the manager with a month's worth of plate appearances in all-important second spot in the lineup. Despite struggles, Diaz felt that he had diagnosed some of the issues that were troubling him. From a Rick Hummel piece in the Post-Dispatch:
"Last year, I was swinging at more balls over the plate and not missing the fastball," he said. "One thing that’s changed this year is that I’m missing the fastball in the middle of the plate. I’m struggling right now but, even with that, I’m still hitting .260."
Lately, Diaz has been trying to pull the ball more, which really isn’t his game. "That’s one thing I have to work on for the next couple of weeks — that pitch outside, I have to be able to hit it the opposite way. If you look at the good hitters in baseball, they use the whole field," he said.
While actually trying to figure out what the problem is and working on a solution is admirable given other, recent comments by Cardinals about their deficiencies, It would appear Diaz will not get the opportunity to make those adjustments at the major league level.
The benefactor here is clearly Paul DeJong. The Cardinals new shortstop has relatively little experience there, with just 50 games in the minors. Since coming to the majors, he has a 111 wRC+, which is certainly adequate for a shortstop or any infield position. His game right now is power and with five homers and five doubles he has certainly delivered on that aspect thus far, but there are some concerns, as Ben Markham recently addressed. He's struck out in 31% of his plate appearances and unfortunately been gunned down at the plate four times already.
DeJong might grow into a role as shortstop, although most seem to think that his future lies as a utility player, a role that is becoming more prominent in baseball but never used by the current Cardinals manager. The Cardinals continue to look for answers and make moves in a season that is approaching do or die status. This is another one of those moves.