Ideally, he'd be a SP in AAA this year, but as a Rule V guy, he has to stay up or be offered back to the Yanks (which isn't going to happen). So he may just be stuck with the long reliever role this season and then sent to one of the fall leagues to start stretching out for next year. A lot will depend on how the team goes; if the Sox stay in contention, they aren't going to do it during the season this year, If they fall down towards last year's levels, they very well might.