Chronicles of the Lads

WHAT LEFTIST BIAS?
Adam Kennedy was rested Sunday night against Barry Zito. On the face of it, this makes sense. Kennedy had played every game, and while he has proved himself an everyday player the last two years, he still needs a day off here and there, and you might as well give it to him against a tough lefty like Barry Zito, right?

Well, not so much.

Did you know that Zito, over his career, is tougher on righthanded hitters than lefties? He strikes out .190 RHB per batter and .184 LHB. He walks .087 RHB and .102 LHB. He does allow slightly less homers to RHB: .0199 to .0221. But his Batting Average Allowed against LHB is .239, against a .216 against RHB. His WHIP against RHB? 1.15. LHB? 1.35.

His three-year splits (2001-2003) show him as allowing a .707 OPS against LHB and a .612 against RHB.

Now, there is some degree of self-selection here. Zito faces only the best left-handed hitters, while he faces a number of lousy right-handed hitters (see: Halter, Shane) inserted into the lineup just for him. I don't really know how to control for this, but I know there is one other factor that can explain it: the cut fastball.

We saw this repeatedly Sunday night: Zito moving that cut fastball in on RHB's hands, tying them up, sending them frustrated to the bench. As excellent as his curveball is, Zito has no such equalizer against lefthanded batters. He doesn't have a fastball that tails up and in against them.

There are many things we know about baseball, but there are just as many mysteries. One thing we know is that the platoon factor is real, and that it exists. One thing we don't know is "why." We have lots of ideas: the movement of the ball, better vision, etc., and the truth is likely a combination of many of these factors.

During Sunday night's broadcast, Joe Morgan was talking about how most righthanded hitters can hit lefthanders well because the fastball tails away from them. Now, Morgan says a lot of silly things about book authorship and bunting in the playoffs, but when restricted to pitcher-batter matchups, he is one of the best analysts around. He was also a fine, fine hitter, so I tend to trust him on this sort of observation.

So, the lefthanded pitcher throws a fastball to a righthanded hitter, and it tails away from the hitter. What does this mean? It means the pitcher struggles to come inside, and if he misses and leaves the ball tailing back over the middle of the plate -- BAM. Now, if you're Tom Glavine or Tommy John and you can nail that outside corner and drive everyone nuts, that's great; you're only going to come inside every now and then to make people honest, and you're going to be damn sure to miss in and off the plate.

(If you look up Glavine's splits since 1987, you'll find that he has a tiny edge against RHB in Batting Average Against and WHIP, but that he allows more home runs to RHB and strikes them out less, both by fairly comfortable margins. Again, Glavine faces only the toughest LHB, so that is a factor to consider. But he is not a reverse-type pitcher along the lines of Zito.)

But there is another way, and that way is Zito's way: bust the righty in with the cut fastball. This is especially effective in that the RHB isn't used to seeing a lefty's fastball move in that way. How baffled was Vlad Sunday night? He's never seen the guy pitch before, and he was busted busted busted inside so bad that he missed one over the middle of the plate in his last at bat.

Anyway, that's my working theory. It occurred to me, wouldn't this also be true of righthanded pitchers? Likely so. Who has the most dominating cut fastball of any righthanded pitcher? For my money, Mariano Rivera.

I looked at his career numbers and felt like an idiot. He strikes out vastly more righthanders (.258 to .187), walks them a bit less (.064 to .069), though he allows them more homers (.0200 to .0085).

But then I looked at his three-year splits, and his OPS Allowed against righthanders was .637, but against lefthanders was .446!

Anyway, this is not to say that Kennedy should have played against Zito, because there are a number of factors that go into giving someone a day off, and I'm sure this was just one of them. But AL teams should be advised that LHB may be better equipped to handle Zito than they think. And I'm going to look out for other cut fastball pitchers and see if they maintain a similar pattern. (You know one who did? Jim Abbott. He relied on the cutter, and the splits we have available for him are eye-popping.)