Colorado Rockies pitcher Jason Marquis struggled again last night, giving up six runs in less than five innings to the San Diego Padres, leaving his team on the wrong end of a 6-3 game. The loss snapped the Rockies' eight-game, at-home winning streak and could validate fears that Marquis is a considerably better pitcher during the first half of the season than the second. The Denver Post's Troy Renck points out that for nine straight years, every team Marquis has ever been on has reached the playoffs, but Marquis has only pitched in the playoffs in four of those series. As he comes down the stretch, he becomes a playoff liability, as evidenced by the fact that he's walked 14 batters in his last 16-and-one-third innings. Although Marquis is one of the key reasons the Rockies are likely headed to the playoffs as the National League wild-card team, he may be passed over in the playoff pitching rotation, Renck writes. The Rox are still in a good position, though, as the Atlanta Braves and the San Francisco Giants both trail Colorado by four games. Sporting News notes the Rockies can clinch the playoff spot with seven more wins, a feat that seems perilously challenging; they barely edged past the Padres Tuesday night, 11-10, and they lost last night. On top of that, the St. Louis Cardinals come to town later this week, and they definitely don't suck. Get ready. It's going to be a bumpy ride.