Mariano Rivera Versus Lefties

Yankees' closer Mariano Rivera notched his 602nd career save yesterday, making him the all time saves leader.  And he did it much like the 601 that came before.  Rivera has been as close to a constant that the game of baseball has seen in the last two decades.

This year, Mariano Rivera has mostly been his usual dominant self, although he's had a few rough outings scattered throughout.  Looking at his splits, it seems like lefties, against which he is usually deadly, have hit him a bit better.

First, let's compare his pitch location from this season to the previous three:

Mariano Rivera (Click image to enlarge)

There isn't a tremendous difference, although you can see a bit more pitches out over the middle of the plate this season. 

Mariano Rivera Overall

	G	P	PA	AVG	BABIP	OBP	SLG	wOBA
2008-2010	209	3293	831	.181	.229	.222	.260	.213
2011	61	876	224	.217	.279	.247	.292	.237

The one thing that stands out is the jump in batting average on balls in play. It's always difficult to determine whether a BABIP jump is a result of decreased effectiveness or luck. For relievers, the sample size is fairly low for one season making it even more difficult to surmise.

However, we do know that it is mostly left-handed batters that account for the BABIP jump.

Mariano Rivera vs. LHB

	G	P	PA	AVG	BABIP	OBP	SLG	wOBA
2008-2010	195	1631	423	.181	.221	.226	.251	.212
2011	55	391	106	.238	.289	.267	.327	.261

Opposing left-handed batters have seen more than a 65 point jump in BABIP against Rivera this season. From 2008-2010, lefties had a 17.5% line drive rate. This season, it is up to 21.5%. This is hardly enough of a bump in such a small period of time to suggest Rivera is getting hit harder. So while it's possible more lefty batters have been squaring him up better, the increase in BABIP is probably more a product of luck than anything else. When coupled with the fact that his strikeout rate against LHB has been 21.7% this season, which is unchanged from his previous three year average, it is even more likely that we're not seeing an actual decline in effectiveness versus lefties.

Update on Tuesday, September 20, 2011 at 6:29PM by Bill Chuck

Here's 81 to know about the great Mo!

http://www.billy-ball.com/2011/09/the-great-mariano-rivera/