As a general rule of thumb, don't worry about the park effect unless the player is moving or changing parks.
The park effect has already been taken into consideration with these guys, since they played there last year, and they're numbers have already been affected by it.
As an example, it would be like projecting Clint Barmes to hit even better this year, because this year he's playing in Coors. Barmes numbers already reflect that half his games (or however many before he went down), are played at Coors.
...Boston papers now and then suffer a sharp flurry of arithmetic on this score; indeed, for Williams to have distributed all his hits so they did nobody else any good would constitute a feat of placement unparalleled in the annals of selfishness. -Updike