Once upon a time, Barry Zito won a Cy Young Award. He probably shouldn't have -- I'm not sure how anyone else ever won a Cy Young award when pitching in the same league as Pedro Martinez -- but he certainly was a distinguished pitcher. Then he signed one of the richest contracts in baseball history, flopped, and became a punchline.

The commonly believed reason for his precipitous decline: loss of velocity. The conventional wisdom was that he came into the league throwing 90/91, and slowly declined to Jamie Moyer levels. Something like this:

But the reality is that while Zito lost some velocity, he always sat in the upper 80s. In his Cy Young season, 2002, his average fastball velocity was 87 m.p.h.. The season before he was given $126 million by the Giants, his average fastball was 85.8 m.p.h.. His fastball actually got better in 2009. His performance did not.

In spring training this year, Zito allowed 44 runners in 19 innings. There was panic and outrage. I think I even heard one caller to a sports-talk show suggest a straight-up swap for Vernon Wells. And all of this came after Zito was so optimistic about the coming year, spending much of the offseason working with pitching guru Tom House:

"The skepticism is well-deserved," House said by phone from Los Angeles. "In any sport you're only as good as your last pitch, catch or throw. But I'm a firm believer that in today's world you can pitch into your 40s. Barry is 33. From what I know about him physiologically, there is no reason he can't be like Jamie Moyer and pitch into his 40s. What he has to do is optimize what he has as he goes through the aging process.

"I'm always optimistic. I think he'll be just fine. He might not be a Cy Young again, but he definitely can continue for the next 10 years."

Guffaws. Chortles. Well-deserved skepticism. And then Zito got better. Much better.

We're still talking about three starts, which mean about as much as his spring stats; that is, not much. But something's different. When Zito did well in the past, he did it with a fastball/curve combination. This year, he's relying on a revamped slider. Using linear weights, FanGraphs has the pitch as the most effective slider in baseball this season.

Which could be a sample-size fluke. But the early data at Brooks Baseball confirms that something is different. His release point is different for his slider this year compared to 2010 and earlier; the movement is different, too. And the difference in movement is that there's a little less break. Here's a slider from 2009:

And one from his last start against the Mets:

It's not faster now, but he took a bit of the hump out of his slider. And he's using it differently -- using it (and a cutter he developed this year) to bore in on the hands of right-handed hitters. He isn't just using it when he's ahead in the count, fishing for a strikeout; he's relying on it as his primary pitch:

Percentage of sliders thrown (rank compared to other pitches):

2012: 27% (1)
2011: 8% (5)
2010: 15% (5)
2009: 19% (2)
2008: 11% (5)
2007: 5% (4)

He's taken a pitch that he hardly threw in 2007 (or 2011, for that matter) and made it his primary pitch in 2012. The early returns are that the new Zito is better than the old Zito, who wasn't as good as the old old Zito.

Zito has a new personal catcher this year, Hector Sanchez, and he might be part of the reason things are different. And it might be that when the league knows to look for the slider, they'll make adjustments. We're talking about three starts, after all. But Zito made his $126 million on the back of his curveball. Six years later, he's looking to earn some of that money with his slider.