Have the Red Sox missed him? Yes and no. On one hand, the Sox have been able to move Kevin Youkilis to third base, keeping them among the most productive teams in baseball at the position. On the other, they’ve lost Youkilis’s productivity at first. Without question, the Sox’ best lineup comes when Youkilis and Lowell are both healthy. Now the worrisome part: What is the likelihood the Sox can maintain that lineup in the second half? Curiously, Lowell hit a snag this season at roughly the same point he did last year. If he’s healthy, the job is obviously his. If he is not, the Red Sox must explore trades for a corner infielder, perhaps one they can retain for next season, too. Lowell, like Ortiz and Lugo, is signed through 2010.