http://www.fangraphs.com/blogs/index.php/free-agent-joel-pineiro

Check the link, there’s the difference. Joel Pineiro sucked until he developed a two-seam fastball. He didn’t have one until 2008, and then it became his go-to pitch in 2009, when he basically ceased using his four-seam fastball (which doesn’t have much movement). In 2007, he used his four-seam fastball 54% of the time.  36% in 2008.  11% in 2009.  Meanwhile, he basically didn't HAVE a two-seamer in 2007 and prior, with it only being 3% of his pitches in 2007, but then 23% in 2008, and then a whopping 59% in 2009.

This suggests that the improvement is very likely sustainable to a good degree!

More fun facts:  The new pitch has apparently been generally mis-identified.  It isn't a two-seam fastball, but actually a one-seam sinker.  Helps to explain the increase in Piñeiro's ground-ball rate from around 48% in most years to over 60% last year (among the best in the majors).  This likely also helps explain how he halved his home run per flyball rate from previous years as well.  The only thing that I have a hard time believing he can maintain is his absurd 1.14 walks per 9 innings rate.  I think that might've been best in the majors last year, and while I'm sure that he should be able to keep his walk rate lower than in years past, that rate is just unbelievable and likely to rise at least a little.

Bottom line - he's unlikely to repeat his 3.49 ERA from last year.  But if he can even post a 4.00, that's just incredible from a guy we're calling our 5th starter!

The other cool thing is that it was big Mariner’s fan Dave Cameron that wrote the article back in November, so anytime a Mariner fan gives you shit about this signing… feel free to point this out!

Update:  It wasn't Dave Cameron that wrote the article, it was Dave Allen.  That's too bad... but the point still stands!

Update x2:  Rob Neyer just quoted us from this post:

http://espn.go.com/blog/sweetspot/post/_/id/2107/which-pineiro-are-angels-getting

Of course, being the notorious Angel hater that he is (how many years in a row has he predicted the A’s to win the West now?), he fails to comprehend the key parts of the post. Not surprising.

Now, let me take this opportunity should Neyer still be paying attention to say this: Eff you, you horrible, biased son of a…