Cain's ERA rose to 5.43 and he's now allowed 13 home runs in just 56.1 innings. This is a guy who gave up 21 last year, and just nine in 2011. The strikeout and walk rates are still close to his career norms, but this obviously is not the solid, consistent Cain we've grown used to over the years.
Chris Quick of Bay City Ball has an excellent post, complete with graphs and video, pointing out that Cain's release point is different:
From 2007-2010 Cain had a fairly consistent vertical release point. He lowered it in 2011 and it remained at pretty much the same point in 2012. This year, he’s dropped even further. His pitches, across the board, are coming out of a lower release point these days.
Now, this might mean something, it might not mean anything. Chris does point out that since 1980, Cain is 15th in most innings pitched through age 28, and he'll climb several notches higher as the season progresses. Some of those pitchers burned out -- Fernando Valenzuela, Mike Witt, Bret Saberhagen -- while others had long and storied careers (Greg Maddux, Roger Clemens). I don't believe Cain has ever missed a start in his career, and there have been no reports of arm issues. It could just be one of those stretches. For example, he had a 10-start stretch in 2010 where he gave up 33 runs in 62 innings for a 4.65 ERA.
As Chris writes:
It's possible that, at the moment, Cain is just going through some horrible luck and getting burned on home runs. It's possible that once things even out, he'll look a lot like the guy we've seen pitch in San Francisco for so long. His effectiveness with his new release point will be something to keep an eye on all season long, as the Giants will definitely need Cain firing on all cylinders if they want to compete in the NL West.