Breaking Balls

Well, the end of the Phillies season has had more ups and downs than Rush Limbaugh at a pharmacy, with the pitching staff seemingly able to blow any lead and the lineup able to overcome any deficit. As good as the hitting has been, though, the lineup has not been particularly stable. With a platoon at third and Utley just returning from a month-long DL trip, the infield has been in flux for a while. Catcher is no exception. On opening day, it looked like Rod Barajas would be donning the tools of ignorance most games this season. However, as the season progressed, Carlos Ruiz and last year's feel-good story Chris Coste have replaced Barajas. These days, Charlie Manuel seems to prefer a Ruiz/Coste platoon behind the plate.

Recently, my father asked me why Manuel didn't play Coste every day. Here is my defense of Manuel and Ruiz:

I am actually a big fan of Ruiz's. He's an extremely talented defender, and I think the Phillies are right to look at him as the catcher of the future. He's only 28 (young for a catcher, relatively speaking) and blocks and throws as well as anybody. Yesterday, he caught Yunel Escobar (of the Braves) too far off second after the pitcher, Buddy Carlyle, missed a bunt attempt. He also hit a home run in the game. I think Coste is a good player, and he may be a better hitter now than Ruiz. Here are their lines (AVG/OBP/SLG) so far this year:

Coste:  .311/.336/.456 (106 PA)
Ruiz:   .260/.333/.406 (340 PA)

Notice the difference between them really comes down to the number of singles they have hit. Ruiz has hit fewer singles (which depresses both his AVG and SLG) but has maintained a nearly identical on-base percentage. In fact, Coste has only drawn two unintentional walks all season, compared with Ruiz's 24 in slightly more than three times the plate appearances. A comparison of batting-average on balls in play (BABIP) shows some interesting things, however:

Coste:  .333
Ruiz:  .288

BABIP can be a good measure of luck, because (contrary to a lot of popular opinion) hitters don't tend to have the ability to "hit it where they ain't." Instead, hitters with high line-drive percentages (balls in play that are comparatively difficult to field) will have high BABIP. We can calculate expected BABIP (eBABIP) in a rough-and-dirty way by adding 0.12 to a player's line drive percentage. Here they are:

Coste:  .322 (-.011 difference)
Ruiz:   .293 (+.005 difference)

So we can see that Coste is better at hitting line drives. But if we take away credit for Coste's extra .011 in BA (and generously assume all those extra hits were singles, rather than extra base hits) and add Ruiz's .005 bonus, we get adjusted lines of:

Coste: .300/.325/.445
Ruiz:   .265/.338/.411

Much closer, with Ruiz gaining the edge in OBP. Now consider the fact that Coste is 34 and Ruiz is only improving. To quantify their defense, Baseball Prospectus rates Ruiz as five runs above average in the field, while Coste has been one run below average.

When all these factors are combined, I think there is a very good case for keeping Ruiz as the everday player and letting Coste back him up and pinch hit, hopefully for a playoff run.