Projecting Brian Duensing

Ron Gardenhire announced after Wednesday’s game that Brian Duensing was guaranteed a spot in the starting rotation. This news was pretty much anticipated given Duensing’s performance as a starter the previous two seasons coupled with the other candidates’ injuries and ineffectiveness.

Without question, Duensing pitched admirably for the Twins last season, acting as a vital cog in assisting the Twins to their second consecutive division title. Still, based on his peripherals and his average-ish stuff overall, there are some who believe that a repeat performance is unlikely. On the other hand, Duensing now has proven in two samplings that he is capable of handling the job, perhaps one of those rare breeds of pitchers who consistently outperform their peripherals.

Since we can’t measure heart or analyze his mentality, let’s take a look at some of the data from last year and see if it can tell us anything about his future performance:

Brian Duensing’s Efficiency (2010)
Category:	Selected Outings	MLB Average	Grade
% of PA’s that go to 3 ball counts:	15%	20%	A+
1st batter of inning out%:	79%	67%	A+
3 or less pitch PA’s:	52%	45%	A
4 or less pitch PA’s:	71%	65%	A

(via MyInsideEdge.com)

As you can see, Duensing thrived in this department comparative to the rest of the league. These are the qualities that a manager loves – get the first guy out and don’t lull your defense to sleep by throwing a ton of pitches in an at-bat.

According to BaseballProspectus.com’s run expectancy chart for 2010, the difference between letting the first runner of an inning on base versus retiring him was 0.59 runs. By keeping the first hitter from reaching, Duensing undoubtedly shaved plenty of would-be runs off of his ledger.

This is unquestionably good. The problem occurs when you ask yourself if any of these skills are repeatable. Certainly, Duensing’s ability to pepper the strike zone and entice contact quickly in the count is a skill that can carry over, but then you have to wonder if more of those batted balls in play will start to go for hits – particularly doing the first at-bat of an inning thereby increasing an opponent’s ability to score runs.

Likewise, Duensing also exhibited some bulldog-like tenacity when painted into a corner last season:

Brian Duensing’s Battle Tendency (2010)
Category:	Selected Outings	MLB Average	Grade
% of runners who score:	18%	24%	A
% of 2-0, 2-1 & 3-ball counts ending in outs:	79%	67%	A-

(via MyInsideEdge.com)

With runners on base, Duensing was able to keep runners from scoring and when he fell behind hitters, he rarely let them off the hook and retired 79% of them.

Given these marks, mixed in with his traditional results of a low ERA and an enviable win-loss record, you can see why Ron Gardenhire tapped him as his third starter. However, the concern over those categories is that they tend not to be repeatable.  For example, Duensing’s 18% runners who score mark is also analyzed as left-on-base% at Fangraphs - measuring a pitcher’s ability to strand runner. This quirky video outlines the influences of the strand rate and that someone like Duensing, who had a vaunted 82% left-on-base%, will be vulnerable to regression.

Furthermore, while wowing everyone with his efficiency and his battle tendencies, Duensing did not impress so much in regards to opponents’ contact:

Brian Duensing’s Overall Effectiveness (2010)
Category:	Selected Outings	MLB Average	Grade
Well-hit average  (of AB’s):	.249	.203	C+
Well-hit average (of strikes):	.103	.075	C

(via MyInsideEdge.com)

In general, Duesning’s offerings, when put into play, were fairly well struck. The well-hit averages were not absurdly high, mind you, but enough to lend credence to the notion that Duensing’s miniscule batting average on balls in play in 2010 is likely to change routes next season. Along those same lines, as I discussed last month, right-handers have slapped him around a bit more and with an increased exposure to opposite-handed hitters, Duensing will likely see some of those numbers inflate to some extent.

Additionally, as impressive as his 7-2 record was as a starter last year, some of that has to be attributed to a substantial amount of offense provided by his lineup. His 5.67 runs per start – the 12th-highest in the AL with a minimum of 70 innings pitched - gave him an ample cushion in which to pitch in, much more so than the league-average of 4.45 runs per game. Given that his runs per start will decrease toward the league average and his penchant for allowing runs will increase some, there will be the likelihood of more marks in the loss column in 2011.

Based on the level Duensing has produced at, it imposes an unreasonable expectations for his future production when considering some factors like his miniscule batting average on balls in play and astronomically high left-on-base rate. Of course, none of this means that he shouldn’t be in the rotation –after all, he has not allowed many home runs and has kept opponents off-balanced enough to get them to drive the ball into the ground - it’s just a friendly reminder for people to keep their vaunted expectations in check. If the defense behind him can convert, he’s likely headed for an ERA closer 4.00 which, all things considered, is not a terrible rate.