What's a 0.00 ERA usually mean?
In many cases, it means that a pitcher hasn't pitched yet, or he's pitched in very, very limited duty without giving up a run.
In the case of Al Levine, it means, "Thanks, but no thanks."
The Giants have released Levine as well as Wayne Franklin, two moves that were generally expected. Levine's release could be viewed as a surprise by some, as he had not allowed a single run in nine innings of work, with a couple of saves to go along with a few wins.
Levine pitched for the Royals a bit during their surprise 2003, where I found him to be one of those "gets it done somehow" sort of pitchers. None of his numbers, except ERA, might suggest that he's any good: he's never had a high strikeout rate, never had a particularly low walk rate, never had a good k/bb ratio, has never suppressed power...he has, however, managed to have a sparkly, shiny ERA below 3.00 twice in the last four seasons, and he was something short of poor in the other two seasons, so it's not beyond belief that Levine could hook up with another ML team within the next week or so. I wish him luck, but I don't think he'll need it. He'll find another job.
Franklin, on the other hand, has never managed to do anything in his career outside of being an "innings-eater" for the 2003 Milwaukee Brewers, giving up 36 homers in 194 innings pitched. Innings-eaters have their uses, but as Franklin is a reliever now, that innings-eater tag turns to "long reliever", and a poor one at that. The Giants have a plethora of candidates for this job, all of whom are either younger or better. Franklin is, by all accounts, a great guy, but a great guy who needs to pitch a lot better if he wants to stay in the league. I wish him luck because he really, really needs it, otherwise "non-roster invitee" and "minor league contract" are going to be some other phrases that'll apply to Franklin in the near future.