Zach Wilt: Breaking down Britton’s successful opening day sinker

Every time Zach Britton took the mound this spring, a number of scouts from opposing teams eagerly watched the Orioles lefty work. The 27-year-old impressed over his 10 2/3 innings in the Grapefruit League, allowing just two runs (one earned), scattering six hits, walking four and striking out 11. Britton is out of options, so if he didn’t make the ballclub, he would have been a valuable trade candidate for any team seeking bullpen help.

On opening day, we saw Britton do just that. It was impressive not only to see him relieve Chris Tillman and earn the win while throwing two clean innings, allowing just one hit and maintaining the O’s 2-1 lead. But what pleased me most was how he recorded those outs - all six came on ground balls. Britton forced Grady Sizemore, A.J. Pierzynski, Will Middlebrooks, Daniel Nava, Dustin Pedroia and David Ortiz to ground out, surrendering just a double to Xander Bogaerts in the sixth inning.

Of the 21 pitches he threw, 19 were sinkers and they were clearly effective. Let’s have some fun with this super small sample size and break down those 21 pitches.

According to the PITCHf/x data from, Britton’s two-seam fastball (sinker) averaged 94.58 mph on Monday. That’s up nearly 2 mph from his average velocity on the pitch between 2007 and 2013 (92.64 mph). He was able to keep the sinker in the zone, forcing a 75 percent zone swinging percentage. In 2013, opposing batters swung at Britton’s pitches in the zone 61.2 percent of the time.

The patient Red Sox lineup, which forced Chris Tillman to throw 104 pitches (71 strikes) in five innings of work seemed to jump on Britton early in the count.

Sizemore saw five pitches (the most of the seven batters Britton faced), while Bogaerts, Pierzynski, Nava and Ortiz saw three, Pedroia saw two and Middlebrooks saw just one. Last season, Nava ranked 14th in the big leagues in pitches per plate appearance (4.11) last seson, and Pedroia ranked 17th (4.05). The patient Red Sox fouled off just 20 percent of Britton’s 19 sinkers, swinging at missing at 10 percent of them. Last season, opponents fouled off 34.92 percent of Britton’s sinkers, whiffing at 10.32 percent.

Interestingly, Britton’s sinker had less horizontal and vertical movement on Monday than it has had between 2007-2013. PITCHf/x measured his sinker with an average of 8.80 inches of horizontal movement and 3.08 inches of vertical movement compared to 9.57 and 6.01 over those previous seasons. Perhaps less movement will cut down on Britton’s walks per nine, where he averaged 3.83 last season and issued zero on Monday.

Perhaps the most telling statistic in this overanalysis of Britton’s two innings of work is the groundball-per-ball-in-play total. In 2013, 66.67 percent of balls in play against Britton were on the ground (61.79 percent between 2007-13). On opening day, 85.71 percent of balls in play rolled through the infield grass. That’s the stat to keep an eye on the rest of 2014.

What do all these numbers mean? How much can we really take away from two innings of relief work? Not much at all. The sample size is small, but Britton’s potential as a former third-round pick is high. If he can continue to keep the sinker in the zone and force ground balls, the O’s bullpen could be even stronger in 2014 than it has been over the previous two winning seasons.

Zach Wilt blogs about the Orioles at Baltimore Sports Report. Follow him on Twitter: @zamwi. His views appear here as part of’s season-long initiative of welcoming guest bloggers to our pages. All opinions expressed are those of the guest bloggers, who are not employed by but are just as passionate about their baseball as our roster of writers.

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