Saturday, October 17, 2009

Tigers Pitching and Defense Improved in 2009

The Tigers were not very good at scoring runs in 2009 but they were pretty good at preventing runs. Their 745 runs allowed was 5th lowest in the league and only 13 runs more than the second lowest team (7 more if you subtract game 163). They also allowed 112 runs (or 0.7 runs per game) fewer than they did in 2008 when their staff surrendered 857 runs. Where did that improvement come from?

Table below lists the fielding independent events in 2008 versus 2009 (Data were extracted from FanGraphs). These are the things that pitchers control essentially without the help of their defense - strikeouts, walks, hit batsmen and home runs. The pitchers struck out about 0.7 more batters per nine innings and walked roughly 0.3 fewer in 2009 versus 2008. On the negative side, they allowed more home runs in 2009 (1.07 in 2008 versus 1.13 in 2009). This resulted in a 0.26 reduction in FIP (the ERA you would expect based on strikeouts, walks, hit batsmen and home runs). So, pitchers were better at things that they can control this year but not 0.7 runs per game better.

Table 1: FIP Stats for Tigers Pitchers - 2008 vs. 2009



















Based on the above, there was more to the Tigers improvement in run prevention than fielding independent events. Much of the improvement came on better results on balls in play. The batted ball data is shown in Table 2 (FanGraphs again). The BABIP (Batting Average on Balls in Play) of Tigers pitchers decreased from .307 in 2008 to .298 in 2009. A lower BABIP is typically an indication of better defensive support but some of it could be pitchers allowing more fieldable balls.

While the influence of pitchers on the results batted balls is limited, they do have a decent amount of control over what kind of batted balls they allow. The line drive rate of Tigers pitchers decreased from 19.4% in to 18.4%. Their ground ball rate increased from 42.0% to 42.7%. Both of these are positive changes. On the other hand, their outfield fly ball rate went up and their infield fly rate went down.

The tRA statistic builds on the FIP statistic by adding batted ball data (LD%, GB%, OFFB% and IFFB%) to walks, strikeouts, hit batsmen and homers. Their tRA (measured in runs rather than earned runs) went from 5.44 in 2008 to 5.11 in 2009. That's 0.33 runs better which still doesn't come close to the 0.7 run per game improvement overall.

Table 2: Batted Ball Stats for Tigers Pitchers - 2008 vs. 2009






















All of the above suggests that the Tigers pitching was better in 2009 but that they also received a lot of help from their fielders. Their 2008 Ultimate Zone Rating (UZR) of -39.1 indicates that their fielders were 39 runs below the average team. Their 2009 UZR of +45.1 was about 84 runs better than 2008. That's about 0.5 runs per game better. Based on this, it appears that fielding was a little more responsible than pitching for their better run prevention.


  1. I think saying that the defense was that much better is somewhat misleading. For example, Justin Verlander's seasons were not fixed changed simply because of improved defense. Batters were not making anywhere near the same contact they were against our pitchers and the defensive plays were much easier. Zone rating does not account for how hard a pitch gets rocked past someone compared to a gentle Porcello induced ground ball. The defense was improved no doubt but the pitching was tremendously improved.

  2. UZR does account for how hard a ball was hit. In the UZR system, each ball is tracked and is judged as hard/medium/soft. In your example, you are saying based on memory that Porcello allowed a lot of softly hit balls. The UZR video scouts are taking each ground ball allowed by Porcello and determining how hard it was hit as it happens. They might get some of them wrong but I'll take live tracking over memory.

    I would agree that Verlander was not helped much by defense. He gets a lot of strikeouts and is a fly ball pitcher on a team which had better infield defense than outfield defense. Verlander was better because he pitched better.

    I disagree on Porcello. He was helped a lot by the strong defense. What do you think his ERA would have been with the 2008 infield behind him? I give him credit for inducing a lot of ground balls but that won't work without good defense.


  3. I wasn't aware that it accounted for that and I agree about Porcello having a higher ERA if he had last years defense but I feel it is very hard to compare with all the changes on the staff. The only two constants were Verlander and Armando. I'm excited to see the new defensive FX cameras to be installed to get a much more accurate idea of judging defense.

  4. for anyone who is unfamiliar with the system that will help better evaluate defense.

  5. I'm also interested to see how the new cameras aid in evaluating defense. I probably trust the current stats more than a lot of people do tough. I don't trust fielding stats as much as hitting stats but I think they are as reliable as pitching stats. I think UZR is as reliable as FIP and perhaps more reliable than ERA.


  6. I just wish there was a better way to measure things like 1st basemen scooping balls in the dirt and such. How do you project Porcello to do next year? I know he had a relatively high BABiP but do you think that one more year of experience and improvement will be able to offset that?

  7. I think what Porcello did at age 20 was amazing. He's still developing so I'm not worried much about BABIP and FIP indicators with him. I believe his k rate will increase next year and he'll be a more complete pitcher. I think his ERA will go down next year too.



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