The Los Angeles Dodgers and Boston Red Sox have become the frontrunners to acquire Toronto Blue Jays ace Roy Halladay, according to baseball sources. Blue Jays GM J.P. Ricciardi has asked for as many as a half-dozen prospects in return for Halladay. Starters Chad Billingsley and Clayton Kershaw have not been offered, and neither have any of the team?s starting position players. Boston's offer includes top pitching prospect Clay Buchholz, as Yahoo! Sports reported Wednesday. The Blue Jays also have been given the choice of reliever Justin Masterson, Triple-A pitcher Michael Bowden or Double-A first baseman Lars Anderson, with lesser prospects from the farm system filling out the Boston offer.