I doubt he sticks. Sox rotation looks like this:
These 3 are must-stays
Wakefield (great as a 4th/5th starter because he's an "off-speed" guy, and because he eats so many innings)
Colon/Schilling/Buchholz/Masterson competing for a No. 5 spot
I really don't see him getting too many innings. Colon's getting paid a decent amount of money now that he got called up. Schilling will obviously be in the rotation once he gets back from injury (ego+contract+career history). I'm not even sure how the Sox are planning to get Buchholz innings this year, let alone Masterson.
However, as a Sox fan, I must say I LOVE the rotation depth, and the fact that four of those guys are pretty young...