Deciding on Duke (plus some interesting catching numbers)

I came across this interesting numbers breakdown on Bloomberg Sports earlier today that shows the best and worst catchers in the league this season when it comes to framing pitches. Kurt Suzuki found his way into the top three in two categories, and they're not good ones. According to Bloomberg's numbers (ranking catchers who have been on the receiving end of at least 1,000 strikes or balls), based on PITCHf/x data, Suzuki ranks last when it comes to percentage of strikes that are called balls, at 24.78 percent. In other words, nearly one-quarter of the pitches that Suzuki receives that are in the strike zone are called balls. Suzuki's numbers in this category are 25.3 percent worse than the average catcher, per Bloomberg's numbers. In addition, Suzuki has gotten just 4.76 percent of pitches out of the strike zone called strikes, which is third-lowest among qualifying catchers. His numbers here are 23.2 percent worse than the average catcher. What's it all mean? It means that when throwing to Suzuki, Nats pitchers have had to work a bit harder to get called strikes than most pitchers across the rest of the league. It's also important to note that this is unscientific and there are other factors at play, including the various umpires calling the balls and strikes. Meanwhile, when the Nationals decided they wanted to stay in-house and use a long reliever on their 25-man roster to make a spot start in place of Ross Detwiler, they had their choice between Zach Duke or Craig Stammen. Here's what those two guys have done so far this season: Duke: 15 innings, 8.40 ERA, 1.733 WHIP, 10 strikeouts, 4 walks Stammen: 20 innings, 2.25 ERA, 1.000 WHIP, 22 strikeouts, 5 walks So why are the Nationals starting Duke tonight against the Giants - the guy with the significantly higher ERA and WHIP - and leaving Stammen in the bullpen? Well, there are a few reasons. First of all, Stammen has been incredibly valuable in his current role, serving as both a right-handed long reliever and also a set-up man at times. If you take him out of that spot and move him into the rotation, even if it's just for a day, he'd be unavailable for the rest of the San Francisco series. With Henry Rodriguez rarely seeing action in high-leverage situations and Duke more of a straight long reliever, that would leave the Nats bullpen really short in the late innings for all three remaining games out west. You also don't really want to mess with a guy who has been so dominant in his current role. Moving Stammen around would throw off his routine, and given that the right-hander has allowed just one earned run and struck out 16 in his last 15 innings, the Nats feel it's better leaving him be. Duke, on the other hand, is used less frequently. He's only appeared in nine games this season, and as a guy who has made just 21 relief appearances over his nine-year big league career, he's not used to throwing so few innings. Having him go out and get a lot of work tonight could tire his arm out (in a good way) and allow him to get back on track. Duke has been a starter as recently as last season, when he went 15-5 with a 3.51 ERA at Triple-A Syracuse. He should have no problem reverting to the starter's mindset, and the Nats hope he can channel some of the form he exhibited last season in his start tonight. If Duke falters, Stammen will be there to back him up. Even if Duke pitches well, there's a good chance Stammen gets into the game tonight in the middle innings. But the Nats felt it was important to keep Stammen in his current role and also give Duke a shot to find a zone. They're leaving the hotter pitcher in the bullpen, but they feel it's the smarter move on multiple fronts in the big picture.