You know that disclaimer that mutual funds give you?

You know, the one that tells you "past performance is no guarantee of future results"?

It basically applies to guys who throw a perfect game.

There's no guarantee that the next start will be great, or even good. In fact, as often as not, the next step after perfection is mediocrity.

Just something to keep in mind as Philip Humber takes the mound Thursday night for the White Sox, one start after his perfect afternoon in Seattle.

Take the last 11 "perfect" pitchers before Humber, which takes you through everyone who has thrown a perfect game in the last 40 years.

In the next start after the perfect game, those pitchers were a combined 4-5 with a 4.48 ERA.

Some were very good (Roy Halladay, David Wells, Randy Johnson). Some were not very good (David Cone, Kenny Rogers). Most were just average.

For some, the perfect game was followed by a long run of imperfect starts. Dallas Braden was winless in his next nine starts. Mark Buehrle threatened for 5 2/3 innings to throw a second straight perfecto, but he lost that game and ended up with an eight-start winless streak, with a 5.44 ERA.

What does it mean for Humber?

It doesn't necessarily mean anything. But for all the deserved celebration of what he did last Saturday, being perfect one day is no guarantee at all that he'll be even good in the starts to come.