I am probably wrong, but I did have the impression in the recent 4 game series that the Orioles pitchers were far more aggressive than the Sox pitchers about getting that 0-1 count. They were helped of course by the Sox tendency to take the first pitch.
When our guys were pitching, on the other hand, I think most Orioles hitters had the green light to swing at first pitch fastballs near the center. And they had the green light because like 80% of the time, maybe more, the first pitch by a Sox pitcher is a fast ball.
Feel free to comment because I'm not at all sure about the above.