Earlier this week it was reported that Huston Street would take Matt Palmer's place on the 25 man roster, but things are a bit more complex and messy than that. Bottom line is that Huston Street will be active for tonight's game against the Giants, but some other roster machinations occurred.
Palmer was actually designated for assignment to make room (both on the 40 man and 25 man rosters) for recent acquisition Ross Ohlendorf, who will go to the bullpen. Miles Mikolas then makes way for Huston Street to become the Padres closer once again. With Suppan also designated for assignment recently, the Padres still have room on the 40 man roster for another player. Presumably, that will be whoever is named new 5th starter, which may not happen until this weekend. Candidates are Jason Marquis, Kip Wells and Micah Owings (who recently made a rehab appearance with the Tucson Padres).