Jhonny Peralta's incredible production on defense

Defensive metrics can be difficult to grasp. The desire for three year sample sizes to be confident. Determining credit and blame on easy defensive plays and hard ones seems impossible. Coming to grips with the concept that a run saved is just as valuable as run created. Watching someone with an atypical body-type and poor reputation in his youth thoroughly dominate at shortstop.

Jhonny Peralta has now put together four straight excellent defensive season after beginning in his career as a below average shortstop. In June I attempted to explain a few reasons for his turnaround.

There are differing theories as to how he could have improved, like better coaching, defensive positioning and better conditioning. He has never passed the eye-test, but for many years Derek Jeter passed it when advanced statistics said otherwise. Peralta may be getting credit for positioning he is not entirely responsible for, but because he has always been sure-handed on the plays he gets to, good positioning maximizes his skill-set. According to the Inside Edge data available at Fangraphs, Peralta is above average compared to shortstops when it comes to making likely and routine (60% and above) plays. On likely plays (60-90%), shortstops on average make around 79% of the plays, while Peralta is at 84%. On the routine plays, the average shortstop makes the play around 97% of the time, while Peralta is over 98%.

Peralta continued to excel in the field for the rest of 2014. In my last post on the subject, I created a chart showing Peralta's three-year averages for both UZR and DRS. I have re-created the chart below with 2014 now complete.

The above info puts Peralta in a bit of a vaccuum. We know he is good. The stats above show that he is well above average, but comparing him to his peers and to defensive players as a whole is missing from above. Looking at Peralta's last four seasons show just how good he has been defensively.

Here is a chart showing Peralta compared to other shortstops over the past four years.

The final "Def" column includes the positional adjustment shortstops receive and more playing time helps that number grow, explaining why J.J. Hardy and Peralta are close to Andrelton Simmons despite lower DRS and UZR/150. We are well past the fluke stage regarding Peralta's defense. Expanding the parameters to all defensive players from 2011-2014 also yields interesting results.

The table is sorted by Def. Taking the positional adjustment into account, Peralta has been one of the most valuable defensive players in all of baseball. Catcher defense might still be underrated, but it is not surprising to see catchers and shortstops on the list given they play the most physical demanding positions on the field. Of note, there are three Cardinals on this list. Also, of note, I decided to include eleven players on this list instead of the standard ten for reasons that should be quite clear.

Peralta heads into his age-33 season, likely on the decline, but the performance he has made from Ages 29-32 have been fantastic. Over the last dozen years, here are the defensive leaders at all positions for players' four seasons from 29-32.

I should note that Molina made this list despite having not played his Age-32 season. He will very likely be at the top of it by the end of the year. Peralta's numbers are a little shocking, which is probably why it can be difficult to buy into them. While the above list is not a great set of comps due to differing positions and levels of playing time, four players on that list were still starters in their Age-33 and Age-34 seasons (Molina, Ramirez, and Hardy have not had theirs yet and Punto and Everett were no longer starters.). Scott Rolen, Adrian Beltre, Pedro Feliz, and Chase Utley all started for the next two years and all remained above average defensively.

Jhonny Peralta heads into 2015 without the buzz of a free agent contract and questions regarding his suspension. He has proven himself incredibly valuable to the Cardinals at a very important position. He was extremely durable in 2014, playing in 157 games. At the risk of repeating how underrated defensively Peralta is to the point of making him overrated, I will continue to believe that Peralta is underrated defensively. He is one of the very best defensive shortstops in baseball. The Cardinals will need that performance again in 2015.