A few weeks ago, I used this space to sing the praises of Oakland's infield defense. The A's pitching staff had - and still has - the lowest batting average in the league on groundballs, and I chalked this up to an infield unit with good hands and better range. This was based on the assumption that, over time, teams tend to allow groundballs of pretty even difficulty, and while that assumption may not be correct, I think it's close enough to lend our measure some validity.
If we're going to note the best team, though, then it only makes sense to note the worst team as well. If we're going to label as the best infield defense the team with the lowest batting average allowed on groundballs, then we should have to label as the worst infield defense the team with the highest batting average allowed on groundballs.
And that team? None other than the Florida Marlins, at .262. The Marlins, thus far, have beaten out the White Sox - at .259 - the Astros - at .256 - and the league average - at .234.
How dramatic has the difference been between the Oakland and the Florida infields? Oakland has allowed 366 hits on 1827 groundballs for a .200 average. Florida has allowed 458 hits on 1751 groundballs for a .262 average. Over 1751 groundballs, the difference between a .200 average and a .262 average works out to 108 hits, or roughly three hits for every four games.
That's a big gap. We can see why Ultimate Zone Rating - the pre-eminent advanced defensive metric available to the public - puts the difference between the Oakland and Florida infields at 72 runs. One of them has been the best in the league at turning grounders into outs. One of them has been the worst. Each individual play may not mean very much, but they can add up very quickly.
It perhaps shouldn't come as a complete surprise that the Marlins are where they are. Regular second baseman Dan Uggla, for example, has had a poor defensive reputation for years, and is thought to be nearing a position switch. Regular shortstop Hanley Ramirez isn't the zoo he used to be, but he isn't Omar Vizquel. The now-departed Jorge Cantu got a lot of time at third base, and he's always been a disaster in the field. Wes Helms isn't much. And though it's too early to know what we can make of Gaby Sanchez, he's a first baseman, and first basemen make the least difference in the group.
So the Marlins most definitely had all the ingredients for a lousy infield defense coming into the year, and sure enough, that's what they whipped up. They made life a little more difficult for groundballers like Josh Johnson and Leo Nunez.
Of course, the question is, how much does it matter? And given that the Marlins have also had one of the top offensive infields in baseball this season, that helps a whole lot. All we should ever really be concerned about is overall value, and overall, the Marlin infield has been all right. Dan Uggla's the perfect case in point. Dan Uggla doesn't field like a second baseman, but he doesn't hit like one, either.
So it's not necessarily that great of a concern. Rather, it's just something to note as we near the time for year-end retrospectives. What did the Marlins do in 2010? They swung hard, they limited home runs, and they watched grounder after grounder sneak through to the outfield. So it was, and so it may be again in 2011 in the event of minimal change.