Jeff Locke’s reliance on two-seam fastball is a mixed bag

Jeff Locke has never been, and will never be, confused for a dominant fastball/strikeout pitcher. He has relied almost exclusively on his location and movement while mixing in his off-speed bread and butter.

Appropriately, Locke has shown opposing batters his two-seam fastball more often, attempting to fool batters with movement. According to FanGraphs, Locke is throwing the two-seamer 57.3% of the time in 2015, yet with only middling success, which I will show below.

As a refresher, here is a glossary of terms we will use in judging Locke’s two-seam fastball. LD% is the percentage of batted balls against the two-seam that were hit for line drives. GB% and FB% stand for ground ball and flyball rates, prospectively. New to us here is x-MOV which is the measurement of horizontal movement as the pitch approaches the hitter. The higher this number, the more that it moves in against right handed batters. Lastly, we have two familiar faces in O-Swing % and SwStr%, the first measuring the rate at which batters swing at the pitch while SwStr (Swinging Strike) measures the rate at which batters swing and miss at the pitch.  Here now are Jeff Locke’s career numbers for his two-seam fastball.

Almost jumping off of the page is the increase in two-seams thrown between 2013 and 2014. In ’13, Locke made thirty starts, averaging 5.4 two-seams thrown per start. In ’14 after getting called up, Locke made 21 starts, yet the number of two-seam fastballs skyrocketed, and the average per start, up to 36.1 per outing. Obviously the jump was due to Clint Hurdle and Ray Searage identifying Locke’s weak point as his fastball and emphasizing movement to maximize whatever velocity Locke could muster.

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At first glance, the jump was very encouraging, as we can see a decrease in line drive percentage (albeit an incremental one) with an increase in batters chasing the pitch or missing it altogether, as well as excellent movement.

2015 is a different story altogether. Locke’s two-seam is still being used to the tune of 52.75 pitches per start, yet it is getting knocked around to the tune of an alarming line drive rate. Perhaps most telling is the O-Swing percentage, which has fallen off of a cliff year over year. The pitch is not fooling anyone at this point. Not pictured is the 1.0 career walk-to-strikeout ratio of that pitch, opponnent’s career .281 batting average against the pitch, and the 1.0 walk-to-strikeout ratio, which is the very definition of pedestrian.

Perhaps Locke’s worst start of the year came in his last outing against the Cubs. Lasting only 3.2 innings while giving up five earned runs, FanGraphs shows us that Locke offered the two-seamer 60% of the time during that start.

So if this pitch is so ineffective, why use it with such alarming frequency? Only Hurdle and Searage may know the answer, but with Locke’s relative lack of velocity (overall, his fastballs are clocking in at 90.7 mph on average), there may be no other logical choice.

For Jeff Locke to use his more effective pitches successfully, they must play off of his fastball.

Yet so far in 2015 the only play on the two-seamer has come from opponnent’s bats.

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