With Jhonny Peralta unavailable until at least June, the St. Louis Cardinals appear poised to fill the three-time All-Star's void with internal options at this time. Back in December, general manager John Mozeliak completed a pretty significant trade with the San Diego Padres, acquiring Jedd Gyorko in exchange for Jon Jay. With 220.2 defensive innings at shortstop under his belt, Gyorko's versatility was to provide necessary days of rest for the 33-year-old Peralta—rest he sorely needed, but did not get, last season.
However, let's not sugarcoat it: Gyorko is not an everyday shortstop, not even if it is limited to the first two or three months of the season. While you can potentially "hide" a below average to poor defender in left field, the same cannot be said about shortstop, one of the most demanding positions on the diamond. Gyorko did not play a single inning at short in the minor leagues. No matter how much work is put in on the practice field (and no matter how much help Jose Oquendo provides with positioning), defensive range is certainly not something that increases with age. Thus, keep Gyorko in the role he was acquired for in the first place: a super-utility back-up.
Enter Greg Garcia and Aledmys Diaz.
Despite having only 105 plate appearances at the MLB level, Garcia feels like a "known quantity," and while known quantities do indeed provide value, they tend to be talked about less freqently. Since we do not yet have a grasp on the depth of Diaz's potential, he feels like the more attractive option at this time. Plus, the Diaz-to-starter-at-short discussion has not been limited to Cardinals' writing quarters, either, as Jeff Sullivan of FanGraphs wrote about the situation in his March 7th piece titled, "The Cardinals Already Have an In-House Shortstop."
As so often happens, Diaz had a hot start immediately following the announcement of Peralta's injury (by going 4-for-4 against the Minnesota Twins), but remember, it was one spring training game. Overall, Diaz has been solid down in Florida, slashing .286/.355/.393 over 28 at bats. That being said, Diaz could start every single game for the rest of spring training, and we still would not have a large enough sample size to accurately determine what we can expect in the future, especially considering he will not always facing off against MLB-level talent in these games.
The fact is, Diaz has accumulated a grand total of 58 Triple-A plate appearances in his professional baseball career. If you want to include the Arizona Fall League, okay, but that is still only an additional 82 plate appearances (140 total). Bear with me on this "comparison," but in 2012 (the year Mike Trout was worth an incredible 10.3 fWAR and finished second in American League MVP voting), Trout began the season with Triple-A Salt Lake, racking up 93 plate appearances before eventually getting the MLB call in late April. Sure, Trout got a taste of the big leagues in 2011 (135 plate appearances) before receiving any Triple-A at bats, but the point I am trying to make stands. The best player on the planet was able to make the jump from a handful of appearances in Triple-A to the big-leagues relatively seamlessly, but Diaz will not find his name in the "best player on the planet" discussion like Trout.
Now, I understand that when there is a need, one must fill said need as adequately as possible. At this time, given the state of the roster and the trade market, Diaz just may be the best guy for the job, or, at the very least, be considered the lead rider of the "carousel" Derrick Goold described over at STLToday.com. While I understand the allure surrounding Diaz, one must not forget that Peralta is one of the best shortstops in Major League Baseball, particularly from an offensive standpoint.
No matter how you slice it, the Cardinals will almost certainly experience a decline in production at the shortstop position for the first few months of the season. Instead of getting too caught up in the excitement of a few good spring training performances, let's understand that there will likely be some growing pains for Diaz should he open the season as the everyday (or nearly everyday) shortstop. And frankly, that's okay given the fact that he has, after all, only 58 Triple-A plate appearances under his belt.