Originally Posted by New York Red
You're one of my favorite posters, Rick, so honest questions here: How many of Parra's games did you see this year, and do opponents fear his arm as much as they fear Bruce's? That's the thing I love most about Jay Bruce -- the number of times runners refuse to even attempt an extra base on him -- and something that doesn't show up in any statistical category. It happens seemingly every game with Jay, and many times more than once.
I've watched maybe a dozen D'Backs games over the past few years and Parra's arm is as good if not better than Bruce's. The fans at Tango's fan scouting report also rate Parra's arm as better than Bruce's.
(They basically have Parra with a slight edge over Bruce, Reddick and Francouer as the best RF arms in baseball)
But frankly when it comes to measuring production, our eyes can be deceiving. The human brain is simply not wired to aggregate small events over time with much accuracy. We remember big, unusual, exciting things. And then, once we we see those things, we watch for them. Sort of like noticing all the cars like yours after you buy a new one. We watch Bruce every day and remember him gunning a guy down. And because of that one exciting moment, we then start anticipating it and we start noticing all the times it comes in to play.
But we don't watch other guys, we don't adjust to them and starting watching them closely. And so our guys start to feel exceptional -- further away from average than they actually are, in both directions. Of course, Bruce actually does have a really, really good arm. But the point stands; we lack perspective.
When it comes to evaluating defensive ability, sure, I'm going to want a scouting report. But when it comes to production, the aggregate of performance over time, I'm still going to start with the data. And FWIW, Fangraphs' defensive metric DOES account for an OFs limiting baserunning advancement on reputation.