From Mets Today, under the heading What's Wrong with K-Rod:

As we all know, Francisco Rodriguez’s velocity has gone down in the past few years, and he’s throwing fewer breaking balls. The result is he’s more hittable. I’m not entirely sure why K-Rod started relying more heavily on the change-up over the nasty slider and curve. Personally, I prefer that he made that change (pardon the pun) because the slowball is very effective and it takes much less toll on the arm.

Though, is it a coincidence that K-Rod is now throwing half as many breaking pitches as he did in 2006, and his average velocity has lost a full 4 MPH since then? Or maybe the two are somehow related?

--snip--

So what does it all mean? I’m going to go out on a limb and guess that the left ankle problem is flaring up again. K-Rod didn’t say a word about the injury in 2007, so it wouldn’t be surprising if he was hiding something now. A weak ankle would definitely explain K-Rod’s command issues lately, and could have something to do with his velocity continuing to dwindle. That said, it wouldn’t be surprising to see him start to use more sliders and curves — unless he is also hiding an elbow issue. Oh, and an elbow injury could have been sustained as a result of changing his lower-body mechanics back in 2007.

I snipped the photographic evidence that Rodriguez does look like a somewhat different (and perhaps slightly heavier) pitcher today, compared to 2006.

Is this clearly a bad thing, though?

This season, Rodriguez's ERA is 2.57, virtually identical to his career mark (2.53).

This season, his 3.25 strikeout-to-walk ratio is slightly higher than his career mark (2.83) and will rank as the third highest of his career if that's where he finishes the year.

It's true that Rodriguez has seemed "hittable" this season; he's given up 38 hits in 41 innings, which is the highest rate in his career. But is this because of stuff, or luck? A little of both, I suspect.

Does it seem odd that Rodriguez is throwing more fastballs these last couple of seasons, even as his fastball have gotten slower?

Yeah, a little. But if Rodriguez ever had an Achilles heel, it was walks. His walk rate this year is the lowest of his career (granted by just a fraction). Maybe he simply decided to throw the pitch, slightly more often, that he can locate with precision. Or perhaps his breaking pitches have lost some effectiveness because he's not throwing them as hard, either, so he's decided to throw fewer of them.

The bottom line is that Rodriguez is having a great season. Yeah, he's giving up a few extra hits. I wouldn't worry about that as long as he's striking out three times more hitters than he walks.