for the pitchers is Wins, Quality starts, Saves, K's, ERA and WHIP. i'm a tad over the innings and have gallardo and vazquez going tonight, so i think you're spot on... give him the bench for now. his last two starts weren't all that stellar
Lester is not there yet, but he has the upside of a #2 fantasy pitcher in 2010. He is worthwhile starting against weaker opponents, but don't risk an implosion against one of the toughest opponents in the league.
Lester tends to avoid implosions in big games as evidenced by his numbers against the Yankees last year and his playoff numbers. I definitely would not say the Yankees lineup right now is so much better than last year that I would ignore his stats from last year. Seems like it would be worthwhile to start him in the season opener against the Yankees at Fenway, the biggest game for him so far this year.