Friday, April 30, 2010

Explaining The Rays Fast Start

They are 17-5 while they outscored their opponents 142-73.That works out to a pythagorean pct of .791 or 17.4 wins. So it seems like sabermetrically they are getting what they are supposed to. But they are actually coming up huge in the clutch so far.

Their hitting OPS is .809 while their opponent's is .700. That differntial of .109 translates into a winning pct of .632. based on an old regression I ran. The equation was

Pct = .5 +1.21*OPSDIFF

That would give them only 13.9 wins, 3.5 fewer than pythagoras. Here is where the clutch comes in. Their OPS with runners on base (ROB) is .926 while with none on it is only .710. Last year in MLB, the average for those two was .763 & .741. Teams do slightly better with ROB, but not over 200 point of OPS better like the Rays this year. Of course, a .634 pct would mean 102 wins for the year, which is still outstanding.

Their pitchers have allowed a ROB OPS of .647 while it is .735 with none on. Again, much higher than a normal split. Their ROB advantage is .088 while last year teams usually gave up an OPS of .022 higher with ROB. You might also notice that with none on, the Rays' opponents are out-OPSing them .735 to .710!

But with runners in scoring position (RISP), things are even more startling. Their hitters have a .999 OPS! Their pitchers have allowed only a .515 OPS. Now last year in MLB, the OPS by hitters in all situations was .750 and with RISP it was .761, only slightly better. The Rays are .190 better. On the pitching side, they are allowing an OPS of .185 less with RISP than overall. But last year, teams normally allowe an OPS of .011 higher with RISP.

In close and late situations (CL), their OPS is just .807. But that is only .002 less than overall. Last year in the AL, OPS in CL situations was .721, .043 lower than the overall of .764. For the Rays to be even close to their normal OPS in CL situations is very good.

Their pitchers have allowed an OPS of just .615 in the CL, while it is .700 overall. So that is a gain of .085. Last year the average AL pitching staff allowed an OPS of .759 in all situations, while it was .719 in the CL, a margin of .040. So the Rays this year have doubled that margin.

Finally, a regression gives the following equation for winning pct by breaking down the OPS differential into ROB and none on cases. It is

Pct = .772*ROBDIFF + .508*NONEDIFF + .4995

It projects the Rays to have a .702 pct. Now the earlier regression gave them .634 while their actual pct is .773. So that one was .139 too low. This one raised the projection by .068, meaning that taking into account their ROB performances explains about have the difference. Considering their RISP performance as well would probably close the gap even more.