Guerra emerged as the Dodgers' closer around the All-Star break of his rookie season, 2011, and saved something like 20 of 22 games. He blew his third save of the 2012 in his 11th opportunity, in a game against the Cubs in early May, the Dodgers moved him out of the closing roll, and he never had another major league save. The Dodgers moved Jansen into the role. He's not having a great season, but he's still there in the ninth when the Dodgers are up by three runs or less.
Having not seen Guerra pitch in a long time (I did see him hit in a game against the Reds in which he walked in his only major league appearance), I would be just guessing that he might be coming up to be the closer. Francisco doesn't instill confidence. Webb has been having control issues. Belisario might be tops on my list of pitchers I'd like to see closing games if you insist on designating one pitcher. But that was true before Lindstrom took the mound Monday.