I think most of the points TheGoldenGreek makes about Tazawa would benefit a starter just as much as a reliever with the only exception being how well he pitches with players on base (assuming he isn't a lefty specialist). Obviously, if he continues to put up very positive splits with runners on base, then he would be useful as a mid-inning reliever. (by mid-inning, i mean a guy who enters in the middle of an inning, not middle-inning)

The most important thing for us all to remember is that he has only pitched in the US for one season. Although he is quite advanced, he may still be quite far away from what he will eventually become. If he develops tremendous control his upside could even become a number 2 quality starter in the future. This is unlikely, as few pitchers ever have such good control consistently. But I think we may be a little down on him, since he performed below our expectations at the big league level. But again, this was his first season, give him time. I don't think we will really have a firm idea of what he has to offer until spring training of 2011.

I think the Red Sox should commit to keeping Tazawa in AAA for the entire season until September, unless they are hit with a string of injuries to the major league roster.