For 149 games in 2010, Casey McGehee did an excellent job of producing offense in the 5th slot behind Prince Fielder in the Brewers lineup. He had career highs in almost every offensive category and produced 104 runs batted in. Then disaster arrived from Cuba via Kansas City, and Casey's numbers went into the toilet.
The myth I want to address - and one that may explain McGehee's production (?) - is how willing a pitcher is to deliver a hittable pitch to a batter based on who is coming up next in the lineup. If a pitcher knows that he's not going to find a soft spot in the lineup soon and he needs to work the hitter right in front of him, eventually he's going to be forced to throw a hittable pitch or two, and this benefits the hitter. If there is a giant ball of baseball fumes sitting behind him in the lineup however, someone who is synonymous with the word 'suck' and is famous for being a rally-killer, then they will pitch around the hitter at the plate to face them instead.
Conversely, if the next hitter in the lineup is a hitting force of nature, like Prince Fielder or Joey Votto, then you're going to see a lot of strikes, because your best shot is probably not going to go as far as theirs, and the pitcher will be less likely to be the goat on SportsCenter that night. Taking the easiest example at hand, last night in game 6 of the World Series in the bottom of the 10th inning there was one out with runners at 2nd and 3rd with Ryan Theriot at the plate. The Rangers had a long meeting at the mound and everyone knew what they were talking about - first base was open, and Albert Pujols was coming up next.
There was no way they were going to let Pujols hit. They were pitching to Theriot, and they were fine with whatever the results were. Theriot ended up grounding out and driving in a run, but I suspect that even if Theriot had reached base they would have walked Pujols next - maybe even if the bases were loaded if they still had their 2-run lead. It's just not worth pitching to a guy with men on base whose OPS is over 1.000. But regardless of what you or I would do, the point is that Theriot's plate appearance was sculpted around a greater threat - the guy hitting next.
Hypothesis: Some of Casey McGehee's sucky season can be blamed on his spot in the lineup
Quite a tall order, considering how much Casey's numbers fell, to blame his regression on the guy behind him. And regardless of who is hitting behind you, there's no excuse for a .626 OPS. I'm not going to accuse the #6 hitter of being solely responsible for the power outage, because everyone who wants to keep their job should be hitting better than .223 regardless of where they are in the lineup. But, I'm going to speculate that Casey McGehee was sitting on the fault line in the Brewers lineup, and the numbers were against him the entire season.
First of all, the numbers. If the statement is going to be true, then first we need to show that the hitter behind Casey was significantly better in 2010 than in 2011. This is the easy part:
In 2010 Casey stayed in the 5th spot for almost the entire season (149 games). During that time he had a number of different players hitting behind him. There was Jim Edmonds (35 games), Lorenzo Cain (30), Corey Hart (30), Johnathan Lucroy (12), Chris Dickerson (10), Carlos Gomez (10), Gregg Zaun (7), Craig Counsell (5), George Kottaras (4), Jody Gerut (3), Joe Inglett (2), and Mat Gamel (1).
For the purposes of this discussion, that the pitcher may pitch Casey differently based on the hitter behind him, I would assume that only the known quantities with enough games to establish a pattern would have an effect. That limits it to Edmonds, Cain, and Hart. Combined, those three batted .287/.344/.500/.844. All together the 6th spot hit .272/.323/.468/.791 in 2010.
For 2011, the numbers are much different. Early on, 60 of Casey's 111 games in the 5th spot were followed by Yuniesky Betancourt, who hit .231/.257/.354/.611 in the 6th slot, easily one of the worst performances in the league. For the season, the Brewers #6 hitters batted .240/280/.359/.639. That's a 24% reduction in OPS in the 6th slot from 2010 - a worse drop than Casey's 22% drop.
So the pitcher knows that when Casey is at the bat, the next spot in the lineup is possibly the worst hitting spot in all of baseball. That's an instant recipe for getting nothing good to hit. Well, it makes sense, but can we prove it? Nope. But we might be able to find some more numbers to back the idea up. There are some times when you can't pitch around a guy.
Bases loaded situations come to mind first. In order to show that Casey was productive when pitchers were forced to pitch to him, his bases loaded numbers should be better than his normal stats, and better than the league average, if he's normally the player we expect him to be.
Casey McGehee, 2011 total stats: .223 / .280 / .346 / .626
League Average 2011, b. loaded: .268 / .309 / .414 / .724
Casey McGehee 2011, b. loaded: .273 / .200 / .455 / .655
Small sample size of only 15 plate appearances, but still not encouraging. Although he did have 4 sacrifice flies in those 15 PA.
The next area we can look at might be high leverage situations. When the game is at a crucial junction and the opposition can't afford any extra baserunners or wait to pitch to Yuni, how often did Casey deliver?
Casey McGehee, 2011 total stats: .223 / .280 / .346 / .626
League Average 2011, hi leverage: .251 / .325 / .382 / .706
Casey McGehee 2011, hi leverage: .231 / .309 / .364 / .673
Well, slightly better than otherwise, but below the league average. And that was over 139 PA in 2011.
So as grim as things are looking for our hypothesis, there's one more thing I want to check - RBIs. We know that RBIs are a random outcome that isn't determined by the hitter, but more or less a function of opportunities times luck. So if the opportunities were there, and the luck is equal over the same time frame, the RBIs should be about the same too.
Casey McGehee, 2010 stats with RISP: 86 RBI in 196 PA
Casey McGehee, 2011 stats with RISP: 59 RBI in 186 PA
While looking at the numbers however I saw something else interesting. With virtually the same number of PA, McGehee had almost the same numbers of K, BB, GIDP, and SF. He hit 4 fewer HRs, and the big difference was a 2010 BAbip of .314 vs. 2011's BAbip of .239 - a difference of 24% - about the same as the difference between his 2010 and 2011 OPS.
So the hypothesis doesn't pan out, and we can't blame Casey's lack of production on Yuni, as much as I would like to. And I'd need someone else to tell me what the difference in BAbip can be blamed on. Although, seeing that his HR numbers are down significantly as well, I don't think it's just a measure of fielding or luck. I think he just hasn't been hitting the ball squarely.
And sadly, Yuni is off the hook. Casey's problem is his own to fix.