Speier in the Glob takes a deep dive into the numbers with Jeff Stern from TruMedia Networks, an analytics firm that uses Statcast data and consults with major league teams.
"With Detroit, Martinez had graded as well below-average. After his trade, UZR and DRS offered favorable numbers for his work. Martinez recalled a conversation with Arizona head of analytics Mike Fitzgerald in which he discussed the disparity.
“My [UZR] has always been a negative in the outfield,” recounted Martinez. “Then I go to Arizona and my [UZR] is positive. I go, ‘What’s the difference?’ He said, ‘Now we’ve got you positioned right.’ ”
According to a major league source, Detroit ranked among the bottom few teams in the majors in outfield defensive positioning last year. Arizona was among the best. The difference was reflected in the defensive numbers Martinez delivered with the D-backs."
Another possible explanation for why Martinez could have rated so poorly last year with Detroit, but much better with Arizona later in the same season:
"The start of Martinez’s 2017 season was delayed by a sprained foot ligament that diminished his speed.
“I couldn’t run, but they needed my bat,” Martinez said. “When I was in Detroit, they were like, ‘We need your bat. We don’t care if you get to those balls.’”
Thus, Martinez played, and his numbers may have taken a hit."
Interesting note on sample sizes for outfielders:
"Most plays for an outfielder are either completely routine — made something close to 100 percent of the time — or completely impossible. Over the course of a full year, there are only about 50-100 plays that are neither routine nor impossible. As of the All-Star break, TruMedia had Martinez involved in just 14 outfield plays that didn’t involve those two extremes, with such a small sample creating a risk of distortion."
So what's the deal? Is JD a good outfielder, or what?
TruMedia says he is solid overall, better in RF than LF:
"That said, among those 14 plays, TruMedia — which graded his defense as below-average in 2016 and 2017 — had his overall body of work as being average to slightly above-average this season. While Martinez has failed to make a couple of relatively high-probability plays, he’s offset those with a couple of very good plays (the one in Toronto, another in Texas) in which he ranged back into the gap. Interestingly, TruMedia graded him as above-average in right — where he’s played for most of his career — while characterizing his work in left as slightly below average."
Overall, a really interesting article that brings to light some stuff about defense and publicly available stats that should be of interest to SOSH.
"With Detroit, Martinez had graded as well below-average. After his trade, UZR and DRS offered favorable numbers for his work. Martinez recalled a conversation with Arizona head of analytics Mike Fitzgerald in which he discussed the disparity.
“My [UZR] has always been a negative in the outfield,” recounted Martinez. “Then I go to Arizona and my [UZR] is positive. I go, ‘What’s the difference?’ He said, ‘Now we’ve got you positioned right.’ ”
According to a major league source, Detroit ranked among the bottom few teams in the majors in outfield defensive positioning last year. Arizona was among the best. The difference was reflected in the defensive numbers Martinez delivered with the D-backs."
Another possible explanation for why Martinez could have rated so poorly last year with Detroit, but much better with Arizona later in the same season:
"The start of Martinez’s 2017 season was delayed by a sprained foot ligament that diminished his speed.
“I couldn’t run, but they needed my bat,” Martinez said. “When I was in Detroit, they were like, ‘We need your bat. We don’t care if you get to those balls.’”
Thus, Martinez played, and his numbers may have taken a hit."
Interesting note on sample sizes for outfielders:
"Most plays for an outfielder are either completely routine — made something close to 100 percent of the time — or completely impossible. Over the course of a full year, there are only about 50-100 plays that are neither routine nor impossible. As of the All-Star break, TruMedia had Martinez involved in just 14 outfield plays that didn’t involve those two extremes, with such a small sample creating a risk of distortion."
So what's the deal? Is JD a good outfielder, or what?
TruMedia says he is solid overall, better in RF than LF:
"That said, among those 14 plays, TruMedia — which graded his defense as below-average in 2016 and 2017 — had his overall body of work as being average to slightly above-average this season. While Martinez has failed to make a couple of relatively high-probability plays, he’s offset those with a couple of very good plays (the one in Toronto, another in Texas) in which he ranged back into the gap. Interestingly, TruMedia graded him as above-average in right — where he’s played for most of his career — while characterizing his work in left as slightly below average."
Overall, a really interesting article that brings to light some stuff about defense and publicly available stats that should be of interest to SOSH.