it's a stat they track over at fangraphs.com, win probability added. their explanation... "WPA is the difference in win expectancy (WE) between the start of the play and the end of the play. That difference is then credited/debited to the batter and the pitcher. Over the course of the season, each players' WPA for individual plays is added up to get his season total WPA." the difference is marginal, and utley is clearly the superior player at this point, i just thought it was interesting to note. it also does not factor in defense. i also agree with thatsfreakinsweet that the largest obstacle to overcome is the bat waggle. if weeks could quiet down his swing i think it would allow his best gifts as a hitter, his good eye and crazy fast hands, to really take over.