Haraz N. Ghanbari, Associated Press Some might say Zach Duke has been pitching in a blur all season.

By Dejan Kovacevic, Pittsburgh Post-Gazette NEW YORK -- For all the frustration accompanying Zach Duke's opening third of the season, for all the exasperation that comes from seeing Oliver Perez highlights on TV, it might be going completely undetected that four-fifths of the Pirates' rotation appears to be benefiting from the influence of pitching coach Jim Colborn.

Ask them, and that is what they will say. Emphatically.

"He's helped me so much," Shawn Chacon said of Colborn. "If you go back to where we were last year and how I'm throwing now ... it's meant so much for me to have him."

"It's great to know he's there," Gorzelanny said. "I can't say enough about it."

Others will offer similar testimonials, but more important are concrete examples, and there are plenty.

It starts with Gorzlanny and Ian Snell, each among the National League's finest so far. Gorzelanny credits Colborn for extensive work on his breaking pitches, as well as calming him through a rough spring. Snell credits Colborn for helping him learn to set up batters with offspeed stuff, a trait that has provided the most dramatic upgrade to his game.

Paul Maholm's overall numbers are poor, but his past two weeks have been better. He, too, has credited Colborn, in his case with a push to be more aggressive early in counts.

"We've worked a lot," Maholm said.

Still, it is Chacon's story that stands out the most.

He was a mechanical mess upon being acquired from the New York Yankees last summer and, in September, Colborn completely restructured his delivery -- more than any Pirates pitcher in 2006 -- to use a more upright stance.

The immediate result was an outrageous 10-mph increase in fastball velocity, and the lasting impact has been that Chacon pitched well enough in long relief this year to win a spot in the rotation. In his second outing, he struck out 10.

"Everything is exactly where it was when we put things together last September," Chacon said.

It should not be omitted that Tony Armas fell under Colborn's umbrella, too. Nor is it likely -- or merited -- that Colborn will stop being faulted for having altered any aspect of Duke's delivery or timing after Duke's phenomenal rookie year.

Few would dispute, though, that Colborn's overall effect on the staff has been positive to this point in the season.

Colborn was asked how much any pitching coach pays attention to criticism.

"Normally, there isn't a lot of criticism," he replied. "You do the work with individual pitchers on a daily basis. There are times, like with Chacon, where he was doing some things wrong when he got here, and we went over those one by one by one. Sometimes, your eyes can tell you what needs to be done. But it's also up to the pitcher to implement the suggestions."

A shot across the bow from New York?

It remains to be seen if Perez's terrific work in New York will continue, given his career of inconsistency.

If it does, though, expect the Mets' Rick Peterson, one of the industry's most respected pitching coaches, to hear even more praise than he already has regarding Perez.

Immediately after the trade last July that sent Perez and Roberto Hernandez to New York for Xavier Nady, the Mets brought Perez to Shea Stadium for a brief workout in which the staff determined that just about every aspect of Perez's delivery -- balance, timing, release point, arm angle -- would change with just about every pitch.

He was sent to the minors but returned for the latter part of the season and pitched in the playoffs.

Now, he is 6-4 with a 2.80 ERA. And that fastball that vanished on him in his final two years in Pittsburgh -- the first of those under pitching coach Spin Williams -- has made an even more impressive comeback, routinely touching 95 mph.

Omar Minaya, the Mets' general manager, was quoted last week in a piece on ESPN's Web site as saying of Perez: "If you have those kinds of numbers, you don't just lose it. I saw his potential. The only thing was he wasn't in the right kind of environment."

Where are the Indians? Blame Cleveland

With the Pirates in the midst of 15 consecutive interleague games, and the -- pause for yawn here -- Texas Rangers and Chicago White Sox coming to PNC Park later in the week, some might wonder:

What happened to the Cleveland Indians?

The Pirates had a series by the Lake last year, but that was only because their division was matched up against the American League Central. Not since 2003 have the Indians been to Pittsburgh and, perhaps no coincidence, not since that unforgettable series has PNC Park hopped as it did after back-to-back 15-inning victories in that series.

Kevin McClatchy, the Pirates' CEO, has urged Major League Baseball for years to have his team and Cleveland become what MLB terms "natural rivals." Those are the teams, such as the Yankees and Mets, that meet every year on the interleague schedule, no matter the divisional matchups.

Cleveland's "natural rival" is Cincinnati, according to MLB (and, perhaps, no one in Cleveland, Pittsburgh or even Cincinnati, for that matter). And that is the way it seems set to stay for the foreseeable future.

Why?

For one, MLB's priority in making out its interleague schedule clearly is dominated by generating interest in New York, Chicago and Los Angeles, regardless of how little help those cities need in generating interest in their respective teams.

For another, and this is the one that is difficult to explain, the Indians are believed to be happy with the current arrangement. Sources say that, if Cleveland officials pushed to play the Pirates, the wish would be granted. But they have not.