You may notice two things immediately: First, Jimmie Foxx had a freaking awesome pitching career. But secondly, there’s a pretty big gap between the OPS+ and ERA+ of these two groups, where the top eschalon of batters has an OPS+ near 200 and the top eschalon of pitchers has an ERA+ of 148.
This isn’t a statistical anomaly. Quite the opposite. It goes to the basic premise of offense vs. defense, and a few of you can probably guess what that is.
In pitching, there’s a limit: 0 runs allowed. So as the average is somewhere near 4.5 runs allowed per nine innings pitched, we’re very close to that limit.
In offense, there’s no limit. Theoretically, nine batters can get on base 100% of the time, scoring an infinite number of runs. Pitchers don’t have that.
(I’m not a statistician, but I’d bet what would actually reverse the OPS+/ERA+ split is if the average batter got on base at a clip above .500? Someone back me up on this.)
Anyway, this is why it’s a bit foolhardy to create a team based on defense. At some point, they’re going to have to score runs. The goal should be to have a decent pitching staff with a great offense that gets on base and hits for power. If defense is undervalued, an average offense is not only wanted, but needed. Offensive stats for a player need to be taken into team context.
The team that understood this the best was the late ’60s, early ’70s Orioles, where Mark Belanger and Paul Blair’s defense were allowed to play BECAUSE the rest of the offense was so sharp. Brooks Robinson and Davey Johnson manned two important defensive positions, but hit above average. And Blair and Belanger also batted at a somewhat serviceable level–it was below average, but it wasn’t bottom-of-the-barrel below.
For example: in 2011, Nyjer Morgan could play center and Yuni Escobar could play SS for the Brewers because of the potent offense at 1B, LF, RF and C. It also helped that Morgan had one of his best offensive seasons ever. Their pitching, likewise, was standard across the board: no pitcher had an ERA+ greater than 111 and only Chris Narveson had an ERA+ below 102. This helped greatly in the playoffs. Same with the 2011 Cardinals, that ended up winning the whole thing.
Unfortunately I have to end this here (on vacation), but I’m willing to bet after some research you’d be able to find that the most successful teams–the ones that went to the playoffs year in and year out–were teams with very good offense and decent pitching while teams that had very good pitching and decent offense made the playoffs on a year-to-year basis. Examples of the latter: 2010 Giants, 2005 White Sox, 2006 Tigers, 2005 Astros.