Who do you think is going to have that "breakout" season this year? It can be a Red Sox player, or from another team if you like.
Mine is Jon Lester. I know he has had two solid seasons already. But I believe he assumes the Sox "Ace" role and runs with it. With Beckett and Lackey pushing him, I think he will be a top contender for the AL Cy Young award at the end of the season. And establish himself amongst the elite SP in baseball.
2010 line: (prediction)
35 starts, 20-5 W-L Record, 2.95 ERA 220K's 65 BB 215 IP