Brian Duensing needs to get right against the right

Brian Duensing entered last night’s start owning the third-highest WHIP against right-handed batters (1.63) – only surpassed by San Francisco’s Jonathan Sanchez (1.64) and Detroit’s Phil Coke (1.77) – in 2011.

This is not any accident of sample size either - including last season the Twins’ left-hander has the fourth-highest WHIP versus righties among qualified starters. It is an amazing contrast considering he has managed to compile some impressive numbers against his southpawed brethren. Since 2010 he has a baseball-best 0.81 WHIP with the fourth-lowest .187 batting average when facing same-sided opponents.

When facing lefties, Duensing’s approach is to work the fastball in on the hands and then unleash his sharp slider off the plate down-and-away. Lefties have found this extremely difficult to hit hard – if they make contact at all - beating the ball into the ground 52% of the time in 2011. This means very few extra base hits. Pepper in his ability to get them to chase the running slider and it equates to one bad mamma-jamma.

Of course, the world is dominated by the right-handed and Duensing has certainly played the role of the submissive this season.

His plan of attack against righties seems strikingly similar but for his secondary pitches. In terms of his fastball, Duensing targets the outer-half of the plate. Rather than using his slider like he does for lefties, he favors his change-up instead. Because he prefers to use a backdrop slider – locating the pitch on the outer-half of the plate to righties – the offering sees less horizontal movement. This gives righties a better opportunity to make contact. The changeup, while effective, is not nearly the same swing-and-miss pitch that the slider is. Hence, in order to be successful Duensing needs to work down in the zone and get grounders.

He did that quite well last year, as you will see in the chart below, but the Twins starter is not achieving the same results on batted balls as he did in 2010. Rather than the high amount of grass-killers, hitters are squaring up on his pitches more, hitting them for ropes around the ballpark:

Duensing’s Batted Ball Distribution vs Right-Handers
	Line Drive%	Groundball%	Flyball%
2010	15.7	52.8	31.5
2011	20.8	40.5	38.7

Using mostly his fastball, he leaves the ball up in the zone far too frequently, even more so than last season:

There is a stark discrepancy between the location of his fastball to right-handers between this year and the last. In 2010 (on the right) Duensing was able to keep his down in the zone – a more difficult spot for righties to hit solidly. This season more and more of his fastballs have been up and over the plate – a much easier place to drive the ball.

That alone is likely reason enough to explain the significant drop in his groundball rate against righties. However, let’s factor in the placement of his most frequently used secondary pitch: the changeup.

While Duensing’s primary pitch to right-handers is his fastball, he mixes in a changeup to keep them off-balanced. Last season, he was far more prone to throwing his change down in the zone, getting weaker contact and likely inciting more hitters to turn over on the pitch. This season, similar to his fastball, the changeup has been up and over the plate. This means opponents would have a greater tendency to drive the ball.  

It was suspected that Duensing would find himself scuffling against the righties and witness regression. On the other hand, one had to wonder if he did have some of those rare intangibles (aggressiveness in the zone, efficient, bulldog-like battle tendencies) that continue to outperform where his peripherals would suggest he should be at. Unfortunately, it has been more of the former and less of the latter in 2011.

With Kevin Slowey putting together a string of good starts in Rochester, fans are beginning to clamor for change in the rotation. With a large deficiency in the standings to overcome, management cannot turn a blind eye to the struggles it much longer. While Nick Blackburn is likely the first candidate to be removed from the rotation, Duensing can’t be far behind. If he wants to remain in the rotation, he needs to keep the ball down in the zone against righties.

Easier said than done.

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