I think the first thing to do is cleanse the palate. Jeremy Affeldt has been a good Giant. And I don't mean in the lofty, "Here is what it means to be a true Giant, man" way, but from a production standpoint. He's a lefty who has shown an ability to get righties out, induce ground balls, and strike hitters out. That's a valuable combination.
Or, to put it another way:
Ahhh. Cleanse the palate. That was one of the better moments in Giants' postseason history (reliever division). Of course, it started with a walk. That's Our Affeldt!, Fridays at 9:30! But then he made the 3-4-5 of Miguel Cabrera, Delmon Young, and Prince Fielder look absolutely awful, which is impressive even if that combination of hitters reminds us all of the seminal Spinal Tap album, Shark Sandwich.
Of all the relievers the Giants locked up, it was Affeldt who made the most sense. His skill set isn't easily replaceable; among lefty relievers who have stayed healthy since Affeldt has been a Giant, only Sean Marshall has been markedly better. Having a pitcher who can stay in for an entire inning, especially when he pitches for a manager as platoon-goofy as Bruce Bochy, is an asset. Especially if he's, you know, effective.
Which Affeldt has not been. He's allowing loud contact, and he's just one HBP away from leading the staff, starters and all. And he's not striking as many hitters out as he usually does. If you want to mess around with the pitch data, you can. He's allowing more line drives to right-handers while inducing inducing fewer ground balls. But we're in small-sample hell with the starters, still. It's much, much more confusing for relievers.
He's started like this before. In 2011, it was the same thing -- wonky control, hit-by-pitches, and a reduced strikeout rate. He got better.
I've spent the last hour looking for an a-ha moment in the pitch data. His velocity is the same. The release points are the same. The movement's roughly the same on all of his pitches. He's getting about the same amount of balls called strikes and strikes called balls (for some reason, umpires don't like Affeldt that much). There is no a-ha moment.
This leads me to a two-part conclusion:
1. There probably isn't anything wrong with Jeremy Affeldt; he's been allowing more hits and louder contact, but we could be dealing with sample-size gremlins. We probably are dealing with sample-size gremlins.
2. The eighth inning should file a restraining order against Jeremy Affeldt until he attends sucking-management classes. That is, he should ply his trade a little earlier in the games, just to make sure. He's thrown 379 pitches this year. More of them have led to unfortunate outcomes than we're used to. That doesn't mean we should read too much into it.
He's probably fine. But he's definitely terrifying. I'm guessing/hoping that he returns to seventh/eighth-inning form by July. But he should be in sixth/seventh-inning situations until then.
Edit: Wait a sec, he's throwing his curveball a lot less than normal. Maybe that's it. Cut that out, Affeldt.