Joe Sheehan of Baseball Prospectus, in a list of 2008 breakout candidates:
I'm not sure how much to make of McLouth's OPS as a starter last year, but it is interesting, and he's been a complete waste of time as a pinch hitter throughout his career after accumulating about an eighth of his career plate appearances there. Stick him in the field, and he's fine.
Another 2007 McLouth split that's interesting:
Facing a pitcher for the first time in a game: .222/.318/.353
Facing a pitcher for the second time in a game: .323/.425/.613
Facing a pitcher for the third time in a game: .388/.455/.816
McLouth's career splits in these areas are similar, though less dramatic.
Of course it makes sense that a hitter would improve the second and third time he faced a pitcher. But McLouth's splits in this area are especially extreme - more extreme than any other Pirate regular's. If these numbers mean anything, they suggest McLouth would strongly benefit from having a starting role.