Entering the 2016-17 off-season, it bordered on heresy to suggest that the St. Louis Cardinals should look into upgrades at shortstop based on production from the position in the previous season. It remains a low-level concern for the Cardinals in the 2017-18 off-season, as well, but for a different reason.
Entering Spring Training in 2016, the Cardinals were planning on Jhonny Peralta, who was excellent in 2014 and the first half of 2015, rebounding and continuing as their starting shortstop. But following an injury to Peralta and to his replacement, Ruben Tejada, the Cardinals turned to Aledmys Diaz, whom the Cardinals had designated for assignment in 2015 in order to make room for Dan Johnson on the 40-man roster. Diaz more than lived up to expectations, belting seventeen home runs on his way to a 133 wRC+. For historic perspective, Diaz was as offensively lethal on a rate basis in 2016 as Joe Medwick and Prince Fielder were for their careers.
Regression was to be expected, but Diaz’s offensive production cratered in 2017. In 301 plate appearances, Diaz drew fewer walks, struck out more often, and batted for less power, on his way to a 78 wRC+. He went from the offensive production of Prince Fielder to the offensive production of J.P. Arencibia. And then on December 2, he was traded to the Toronto Blue Jays for relative non-prospect J.B. Woodman.
Luckily, for the Cardinals, the emergence of Paul DeJong was arguably their most pleasant surprise in a season which included Tommy Pham finishing 11th in National League Most Valuable Player voting. DeJong had a 122 wRC+, not quite as high as 2016 Diaz but clearly above-average, while providing 25 home runs in his rookie season. His defense, derived from small sample sizes as it may be, was firmly above-average statistically and DeJong was on the whole better than Diaz had been during his rookie season. DeJong finished second in Rookie of the Year voting behind Cody Bellinger of the Los Angeles Dodgers, and he deserved such recognition.
Entering 2018, Paul DeJong has firmly established himself as the shortstop of the Cardinals, a fate few expected six months ago. DeJong’s MLB wRC+ of 122 was nearly as productive relative to league average as his 2016 AA wRC+ of 123. He ranked 11st per VEB prospect rankings and 14th according to Baseball America. He was a prospect of sorts, but his level of production in 2017 was by no means expected.
By Steamer projections, Paul DeJong is expected to be a below-average hitter—barely, at 99 wRC+. Even looking strictly at 2017 MLB results and ignoring his lack of prospect pedigree, DeJong’s xwOBA stood at .323, a thirty-six point drop-off from his actual wOBA of .359. Had he qualified for the batting title, DeJong would have ranked 44th among 145 qualified batters in wOBA, a hair below Andrew McCutchen. But had he produced his expected wOBA, he would equal that of Andrelton Simmons (a legitimate down-ballot MVP candidate, but also the best defensive shortstop in baseball) and Trevor Story, considered a bit of a disappointment since his torrid start to 2016.
Steamer does project DeJong to be pretty good defensively, and to the naked eye he does appear to handle shortstop pretty well, but he is also relatively new to the position at the professional level, having come up primarily as a third baseman. Realistically, the Cardinals probably aren’t expecting Paul DeJong to be quite as good as he was in 2017—four-win shortstops, the rate at which he played per 600 plate appearances in the big leagues, don’t grow on trees—but expecting him to still be league average, while certainly possible, also would have been considered a leap of faith a year ago.
And now, over 600 words into a post with his name in the title, we get to Zack Cozart.
As good as Paul DeJong was in 2017, the former Cincinnati Reds shortstop was better. Cozart was worth 5.0 wins above replacement per FanGraphs and 4.9 per Baseball Reference. And this was in 507 plate appearances, in the vicinity of a normal full season’s amount but on a per 600 plate appearance basis, Cozart was better (5.9 fWAR) than two of the three shortstops ranked ahead of him by fWAR—Francisco Lindor (4.9 fWAR) and Corey Seager (5.6 fWAR). Only Carlos Correa outperformed Cozart when on the field last season.
This would seemingly make Zack Cozart one of the most coveted players in free agency this season, but the shortstop, who turned 32 last August, has never produced to nearly his 2017 level before. He has long been a good defensive shortstop, but 2017 was Cozart’s first full season in which he was an above-average hitter (141 wRC+, tied with MVP candidate Charlie Blackmon). While his true offensive talent probably isn’t at the calamitous lows of 2014, when Cozart had a 56 wRC+, a player at his 2016 level of 91, which even after 2017 remains slightly higher than his career wRC+ of 90, isn’t especially inspiring, though he is perhaps a safer option than Paul DeJong.
The Reds did not extend Cozart a qualifying offer for 2018, and while the team is rebuilding and probably isn’t especially eager to pay eight figures to a player for a 2018 season which will almost certainly not culminate in a playoff run, it does suggest that the team does not believe his 2017 is not completely for real.
The underlying statistics suggest that this is mostly correct. And while Paul DeJong’s wOBA exceeded his xwOBA by 36 points, Zack Cozart had an even more pronounced gap—his .392 wOBA was coupled with a .332 xwOBA, good for a 60 point drop. Cozart falls from 15th of 144 to tied for 81st when using his xwOBA instead. Cozart was still a better hitter than DeJong if going by xwOBA, but it was a much smaller gap, one that could easily be closed by another year of DeJong closing in on his prime and another year of Cozart exiting it.
Steamer projects Cozart at a 98 wRC+, slightly worse than it projects DeJong, but as Cozart projects as the better fielder, he is a 0.4 WAR improvement. Because he has a track record of adequacy, if not excellence, Cozart is also the safer option. Of course, acquiring Zack Cozart would also require the Cardinals to spend money on him.
MLB Trade Rumors projects the San Diego Padres to sign Cozart to a three-year, $42 million contract. It’s an interesting match, as the Padres are not likely within striking distance of contention (their rumored interest in Eric Hosmer suggests they may disagree), but it does make sense from a perspective of improving the team’s strength at the position—the position was handled primarily in 2017 by the sub-replacement level Erick Aybar. For the Cardinals, Cozart represents a smaller upgrade, if he is an upgrade at all.
Zack Cozart is at least a good enough player that he would improve the Cardinals—there are lesser free agents where this is more in doubt. But he doesn’t provide the upside to justify $14 million per season—the $13.25 million annual salary to Jhonny Peralta after 2013 made more sense because he was replacing Pete Kozma and/or Daniel Descalso, far lower upside players than DeJong.
Cozart may be worth monitoring closer to Spring Training if his salary comes down, and his term probably wouldn’t conflict with the potential arrival of Delvin Perez, who is likely several years away from MLB-ready, but otherwise, despite concerns about the incumbents, it may be in the best interest of the Cardinals to take their chances on Paul DeJong.