What is in Samuel Deduno's future?
by, 08-16-2013 at 05:42 PM (518 Views)
Since he joined the Twins last year, the question has been asked repeatedly, “Can Samuel Deduno keep this up?” At the pace he was going last year, with almost a 1:1 strikeout to walk ratio, conventional wisdom tells us that he could not. Lucky for him, and the Twins, he has not continued at that pace. Last year, Deduno walked a batter in 15.3% of plate appearances, but this year that number is down to 9.1%. Sounds great on the surface, but in limiting his walks, he has also decreased his strikeout rate from 16.4% to 13.6%. It would seem Mr. Deduno is buying into the dreaded “Pitch to Contact” philosophy, but it is not as if he was a strikeout machine last year anyway, he was below the league average of 19.8%. Deduno’s real calling card all along has been his ability to get groundballs. In 2012, he got a groundball 58.3% of the time and this year he is up to 59.5%. For reference, the league average is 44.6% meaning Sam Deduno is a groundball machine.
With this season down the drains and my focus turning to next season where hope starts to shine a little brighter with the (hopefully) imminent arrival of Sano, Rosario, Meyer, May, etc, I wanted to see what Deduno may bring to the Twins rotation. Where I began was to brainstorm comparable Twins pitchers from recent years who were categorized as groundball, low strikeout guys, namely Nick Blackburn and Carlos Silva. For most Twins fans, those two names are not names that you necessarily want to see popping up when looking for comparables, but lucky for us, neither man provides a particularly good comparison. The best groundball rate either of them posted was a 55.5% by Silva, as a reliever, with the Phillies in 2002. His best as a starter came in 2004 with the Twins, where he got a groundball 50.5% of the time. Blackburn’s best year was the 53.5% that he put up in 2011. While they were both above average at getting groundballs, neither ever did it at as extreme of a rate as Sam Deduno has the last two years.
Instead, I turned my focus outside the organization to see if there was any precedent in recent years for guys with similar numbers to Deduno having success. To find comparable pitchers, I took an idea from a recent Fangraphs post by Jeff Sullivan concerning how terrible the Twins are at striking people out. If you haven’t read it, it is quite interesting, and depressing. But in the piece, Sullivan comes up with a measure K%-, or strikeout rate minus to neutralize the differences between strikeout rates across different years and give a more accurate comparison between different pitchers in different years (100 being average, 100+ above average, under 100 below average). The necessity for this was brought up by the fact that, since 2002, strikeout rates have risen from 16.8% to 19.7%, meaning Deduno’s 13.6% strikeout rate would look a lot better in 2002 than it does this year. I did a similar process with walk rate (BB%), but that was less out of necessity and more for the sake of consistency. Now it should be noted that when looking at these numbers, 100 is average in both, but since we like more strikeouts, anything above 100 is above average for K%-, and since we dislike walks, anything below 100 is above average. This is not ideal, but it was a rough idea to get a quick comparison thrown together. What these numbers revealed was that Deduno’s is 31% below the league average at striking batters out (K%- of 69), but 15% above league average at walking batters (BB%- of 115).
At this point I gathered up all the pitchers from 2002 to 2013 (the years in which Fangraphs has information on batted ball types) who pitched at least 100 innings in a year and searched for any pitcher who had a K%- between 60 and 79, a BB%- of 105 to 125, and a groundball percentage (GB%) of 58% to 60.9%. Now you’ll notice I didn’t create a GB%- because the league groundball percentage has remained fairly stable between 43.3% and 44.6%, therefore a GB%- would not have provided much of a difference. I found 6 pitchers in that time frame who fit the qualifications, Scott Erickson (2002), Jamey Wright (2006), Charlie Morton (2011), Zach Day (2003), and Jake Westrook (2003, 2011). At this point, I just wanted to walk away because this group doesn’t do much more for me than Silva and Blackburn, but I pushed on. Below is a table showing the ERA-, FIP-, ERA, and FIP of those 6 pitcher seasons with the averages at the bottom. I also included a line, “Weighted Average,” that gives more credit in the average to pitchers who pitched more (ie Jake Westbrook 2011 @ 183.1 IP) than guys who pitched less (ie Zach Day and Jake Westbrook 2003 at 131.1 and 133, respectively).
Season Name Team IP LOB% GB% ERA FIP ERA- FIP- K% BB% K%- BB%- 2011 Charlie Morton Pirates 171.2 72.50% 58.50% 3.83 3.77 103 101 14.30% 10.00% 77 123 2003 Jake Westbrook Indians 133 70.90% 59.60% 4.33 4.57 98 105 10.00% 9.70% 61 114 2011 Jake Westbrook Cardinals 183.1 69.10% 59.30% 4.66 4.25 126 114 12.90% 9.00% 69 111 2006 Jamey Wright Giants 156 66.80% 58.10% 5.19 4.89 115 107 11.70% 9.50% 70 113 2002 Scott Erickson Orioles 160.2 66.30% 58.00% 5.55 5.08 128 119 10.30% 9.50% 61 109 2003 Zach Day Expos 131.1 72.20% 59.50% 4.18 4.47 95 100 10.50% 10.20% 64 120 2013 Samuel Deduno Twins 94 75.00% 59.50% 3.54 4.03 88 101 13.60% 9.10% 69 115 Average (non-Deduno) 155.8 69.63% 58.83% 4.62 4.51 111 108 11.62% 9.65% 67 115 Weighted Average (non-Deduno) 69.55% 58.80% 4.63 4.48 112 108 11.76% 9.62% 67 115
Whether I weighted the average or not, Deduno is having the best season of the seven pitchers based on ERA-. By FIP-, he is only eclipsed (barely) by Zach Day.
Why is it that of those seven, Deduno this year is 7 percentage points better than any of the rest compared to league average? To me, it comes down to his percentage of runners left on base (LOB%). Despite what the Twins hitters would lead you to believe over the last few weeks, the average LOB% has hovered in the low 70’s for the entire sample of 2002 to 2013. As we can see, for this group as the LOB% goes up, the ERA tends to go down, so it should be no surprise then that Deduno with his 75% LOB% has the lowest ERA- of the group, he simply been better at leaving his opponents on base. However, LOB% is extremely volatile. From 2002-2012, the only pitching peripheral stats with a lower year to year correlation were Batting average on balls in play (BABIP), Line Drive percentage (LD%), and Home Runs per Fly Ball Hit (HR/FB). Is it a good sign for the last two years he has had LOB% of 77% and 75%, yes because there is evidence that pitchers have a small amount of influence on their LOB%, but not enough to get giddy about, especially when you compare it to his peers.
Where this starts to get interesting is looking towards next year.
Season Name Team IP LOB% GB% K% BB% K%- BB%- ERA FIP ERA- FIP- 2012 Charlie Morton Pirates 50.1 66.20% 56.50% 11.20% 4.90% 57 61 4.65 4.17 121 110 2004 Jake Westbrook Indians 215.2 72.40% 62.60% 13.00% 6.80% 77 79 3.38 4.04 75 92 2012 Jake Westbrook Cardinals 174.2 70.90% 58.10% 14.10% 6.90% 72 86 3.97 3.8 104 100 2007 Jamey Wright Rangers 77 75.70% 54.80% 11.80% 12.40% 69 146 3.62 5.03 78 110 2004 Zach Day Expos 116.2 76.50% 53.60% 12.30% 9.10% 73 106 3.93 4.71 89 104 Average 126.54 0.7234 0.5712 0.1248 0.0802 69.6 95.6 3.91 4.35 93.4 103.2 Weighted Average 72.65% 58.28% 12.89% 7.78% 72 93 3.77 4.23 90 100
Of the six pitchers, the only one to make more than 19 starts was Jake Westbrook in both 2004 and 2012. Scott Erickson was hurt for 2003, so I left him out because I feel like going two years would not have been the best simply, because guys generally spend much of the year getting their feel back.
The big takeaway from this table is that the groups ERA- and FIP- both improved, whether weighted for the fact that Jake Westbrook pitched most of the innings in the sample or not. There is one very big disclaimer that needs to be thrown on this is that the only man whose LOB% did not go up was Charlie Morton and his ERA- went up as a consequence. While that looks promising for Deduno, remember his LOB% is 75% already, and none of his other peers have been able to put up that kind of LOB%, because generally guys with LOB% north of 75% strike people out. One other thing of note, their groundball percentages all went down the next year save Jake Westbrook.
What can we expect from Deduno going forward?
For me, I would expect an uptick in ERA, probably bringing him closer to league average, if not a little over, mostly due to some LOB% regression. Because he has maintained his two year rate at such a high level relative to the group, it makes me hopeful he can maintain that success, but I expect he'll regress because generally guys who have LOB% north of 75% strikeout batters at a much higher rate than Mr. Deduno.
What can we hope for?
Jake Westbrook. If he can maintain his groundball and strikeout rates, and continue to drop the walks even to 8%, that will go along way towards him remaining league average or slightly better. While that doesn’t sound enticing, for this rotation, it practically makes him the ace and maybe a piece that can stick around in the back of the rotation for a couple years.
Should the Twins lock him up long term?
NO! PLEASE NO! To me, while there are some examples of these guys improving, the signs do not point to a guy you want to lock into long term, especially when the Twins can go year to year with him through 2018, plus he is already 30. That way if he absolutely craters, the Twins can simply do exactly what they did last year, non tender him and sign him back to a minor league deal with a invite to Spring Training.
What is in Samuel Deduno's future?
Based on the evidence above, he is a guy who may be able to pitch for a while, but will likely bounce around as a 4th or 5th starter on a couple different teams before retiring in his mid-30's.