Which version of Jhonny Peralta should we expect in 2016?

There is arguably not a weirder career among current members of the St. Louis Cardinals than that of Jhonny Peralta.

And it's not as though there is a shortage of candidates for this title. After all, Yadier Molina was such a poor hitter in 2006 that he was below replacement level while accumulating the second-most defensive runs saved among all MLB catchers, and six seasons later, he had a higher wRC+ than Albert Pujols. But Jhonny Peralta is in his own class of oddity, having transitioned not only into a completely different type of player, but into a type of player associated with youth, a type which Peralta became instead in his thirties.

Peralta, for those who did not follow his pre-Cardinals career, came up as a shortstop with the Cleveland Indians in 2003. And after a 2004 season without considerable playing time, Peralta played the next four seasons, aside from one game at third base in 2008, at shortstop. And in each of the four seasons, he had a negative ultimate zone rating. Although his UZR improved from 2007 to become only slightly below average in 2008, the Indians moved Peralta to third base for the 2009 season. At the age of 26, Jhonny Peralta was moved down the defensive spectrum.

Like his 2008 season at shortstop, Peralta's 2009 at third base was slightly below average. He wasn't Miguel Cabrera, but he also wasn't Brooks Robinson.The transition to third, even for a man as relatively young as Peralta, raised few eyebrows. The Baseball Prospectus annual used the phrase "increasingly immobile" to describe him twice, in 2009 and 2010. Moving away from the most significant non-battery defensive position was just the logical conclusion.

But following a July 2010 trade to the Detroit Tigers, Jhonny Peralta moved back to shortstop. It was not a universally praised decision: the 2011 edition of the Baseball Prospectus annual had this to say about Jhonny Peralta's return to shortstop:

While his bat plays better at shortstop, his glove certainly doesn’t--there’s a reason the Tribe exiled him to the hot corner--making this a regretful decision on several levels.

However, for the next four seasons, Jhonny Peralta was an above average defensive shortstop, while playing almost exclusively at the position. By defensive runs saved, he ranked 2nd among MLB shortstops in 2011, 3rd in 2012, 16th in 2013 (while this clearly represented a step back, it's pretty solid given the context of missing 50 games due to suspension and that he wasn't considered good enough defensively to play shortstop five years before), and 3rd in 2014.

I watched Peralta's defensive renaissance in real time, including very closely starting in 2014 when he joined the Cardinals, and I still can't pretend I understand it. He didn't look the part of slick-fielding MLB shortstop. He has always been a notoriously poor base-runner, even as a young man (in all 13 of his MLB seasons, including the partial ones, his base running runs has been below average, and his season-high in stolen bases was four in 2007). Additionally, his physique is...unimpressive. If you saw Jhonny Peralta in uniform in a dugout with absolutely no context about who he is, you probably wouldn't think he was a shortstop. More likely, you'd think he was a first baseman or a designated hitter. Or perhaps a bench coach.

But this is the story of Jhonny Peralta's career. He defies expectations. When the consensus opinion was that Peralta is limited defensively, he became one of the best defensive shortstops in baseball. When Peralta was suspended for 50 games in 2013 for his role in the Biogenesis scandal and the Cardinals were widely claimed to be overpaying when they signed him to a 4 year, $53 million contract in the offseason, Jhonny had a 2014 which, by both Baseball Reference and Fangraphs WAR, was his best season yet. And the expectation that Peralta set forth with his 2015 season, from its superb beginnings to its floundering conclusion, is that he is a strong candidate for severe decline.

A quick look at wRC+ by month suggests a season in three acts for Peralta. In April and May, he posted a 126 and 158. At the plate in April, he was essentially Jason Kipnis; in May, he was Nelson Cruz. In June and July, his bat went from superb to adequate, with wRCs+ (this is my best guess for the pluralization of the stat) of 97 and 99, respectively. Player comparisons for these totals are Kolten Wong (technically a slightly better version of Wong, whose wRC+ for the season was 96) and Evan Gattis. However, August and September did not go so well, and his monthly wRC+ totals fell to 70 and 74. Five and six qualified hitters, respectively, did not exceed these on the season, out of the 141 qualified hitters in Major League Baseball last season.

The first instinct that many sabermetrically-inclined fans have when seeing a player who regresses as swiftly as Peralta did is to consult his batting average on balls in play, the hallmark statistic for gauging player luck. And unsurprisingly, Jhonny Peralta did have a higher batting average on balls in play in the first half of 2015 than in the second half--his first half BABIP was .331 and his second half BABIP was .284.

But BABIP as a measure of luck is only relevant if we are assuming the difference between a high and low one is the result of ground balls finding holes in the infield, of fly balls missing outfielders and dropping in for hits, etc. Some players are naturally predisposed to high BABIPs. Mike Trout, for instance, tends to rate highly and not just because of luck: Trout has the speed to beat out infield hits and hits disproportionately more line drives and fewer infield fly balls than the league as a whole. So to provide context for Peralta's BABIP plummeting, here is how his first and second half compared to the league's average hitting rates.

Across the board with regards to balls-in-play statistics, Peralta's numbers got worse, though not by leaps and bounds, in the second half. He still hit line drives at an above average rate, and yet he was unable to convert those line drives into a ton of hits. A popular theory was that Peralta declined down the stretch because he wore down, that his age was catching up with him, and that he was unable to get much-needed off days because his backup was Pete Kozma, who in 2015 had the seventh-most plate appearances in a season in the expansion era for a position player who failed to garner a single extra-base hit. And while Peralta would almost certainly benefit from more rest, which may be afforded to him with the presence of Greg Garcia and potentially Aledmys Diaz, it's also possible we are simply overestimating his decline based on his late 2015 raw results.

My previous allusions to his defense aside, Jhonny Peralta will eventually decline defensively. His 2015 defensive metrics suggest that this decline has already begun (though this could also be easily attributed to a small sample size). And his work on the basepaths is never going to be confused with Billy Hamilton's. But, as he has proven in the past, it may be premature and presumptuous to write off Jhonny Peralta just yet.