The Los Angeles Dodgers will send their longtime staff ace to the mound Tuesday in a key National League West clash, while the Colorado Rockies will have their difference maker poised for another second-half masterpiece. September matchups with a division title on the line do not get much better than three-time Cy Young Award winner Clayton Kershaw against outside Cy Young contender Kyle Freeland in a must-see duel of left-handers. The Dodgers will enter Tuesday with a half-game lead on the Rockies after beating their division rival 8-2 on Monday in the opener of a three-game series at Dodger Stadium.