The Dodgers did officially purchase the contracts this morning of infielder Blake DeWitt and Angel Chavez, and DeWitt is in the starting lineup at 3B, batting eighth, for better or worse. “We’re not askign him to do anything other than play the position,” Joe Torre said. “We don’t want him to carry us or do anything extraordinary.” Chavez was taken over Ramon Martinez because Martinez basically because he gives the club more roster flexibility, which is important given that either one would be going back to Triple-A eventually. By adding Martinez to the 40-man roster, the Dodgers would risk losing him when they try to outright him back to the minors because he has enough big-league service time that he could simply refuse the outright, become a free agent and keep his major-league salary for the entire season. Chavez doesn’t have enough service time to do that. … There are indications DeWitt’s stay might be a short one, even though Torre admitted this morning that Nomar will need a rehab assignment before he is activated, which means he isn’t going to be activated anytime soon because he isn’t even close to being ready for game action. But Marcus Giles is still a free agent, has been ever since the Rockies released him on Tuesday. It would make sense if the Dodgers were to sign him and send him to Vegas for a few days to see if he could master playing 3B, where he has made nine career appearances, none since 2005. Then, if he proves he is even adequate, they could bring him up after a few days and stick him in the lineup.