Joe Maddon switched up his rotation this morning by announcing that Scott Kazmir will take the mound in Game 5 at Fenway Park tomorrow instead of James Shields, who's now listed as the tentative starter in Game 6. Because of off-days, Kazmir will be pitching on normal rest, whereas Shields was originally going to be pitching on five day's rest.
Looking at the numbers, it's easy to understand the switch. Shields was lit up at Fenway this year, giving up 11 earned runs while lasting a grand total of 4 2/3 innings over two starts. If the Red Sox force a Game 6, it will be played at Tropicana Field, where Shields has posted a 2.59 ERA this season. Kazmir, on the other hand, has a sterling 3.02 ERA in 11 career starts at Fenway (albeit with a pedestrian 4.50 ERA in two starts this season).
As Chad Finn reports in the Boston Globe, however, there may be more to Maddon's strategy than simply putting his starters where they're most comfortable. Kazmir has some history with umpire Derryl Cousins, complaining after a start in June that Cousins was giving hitters "makeup calls."
Considering Cousins is currently scheduled to take his turn behind the plate in Game 6, it makes sense to move Kazmir up a day to avoid Cousins completely. When asked his thoughts about dodging Cousins, Kazmir told Marc Topkin of the St. Petersburg Times, "That might be a good idea." Given the rest of the numbers supporting the move, it's pretty much a no-brainer.