The Pirates made official what had become increasingly obvious over the past few days: Nate McLouth is their center fielder.

Chris Duffy, the starter at the position on opening day, was optioned yesterday to Class AAA Indianapolis in a move the team said is aimed at keeping him on the field regularly. Utilityman Mike Edwards was recalled to take his place.

"For most of this season, you saw us giving McLouth the tough at-bats against the left-handers, against the Tom Glavines, because we were trying to give Duffy a chance to get right," Pirates manager Jim Tracy said. "Now, you're going to see McLouth take those at-bats."

The Pirates made the announcement after Tracy, general manager Dave Littlefield and Duffy met in Tracy's office for more than an hour after the game.

McLouth, 24, made seven consecutive starts before yesterday, when Duffy made his first since May 4. And McLouth made the most of the chance: He is on a 9-for-22 roll and has reached base safely in 15 of his past 28 plate appearances to raise his season average to .231.

"This is me, what you're seeing right now," McLouth said. "I never really felt like I had a chance to be comfortable before because I wasn't getting out there and taking my swings. Now, I'm feeling good."

Duffy, 26, went 0 for 4 yesterday to drop his average to .194 after he batted .341 in a half-season as a rookie last year.

Starting in January, Tracy urged Duffy to adopt more of a prototypical leadoff approach, to draw walks and hit the ball more the other way and into the ground. Although Duffy was a line-drive hitter all through the minors, he offered no resistance, even when his spring struggles carried over into the season.

Yesterday, he made clear -- to management and, later, to the media -- that the change was not to his liking.

"Before I even played for Tracy, he was already kind of saying what he wanted me to do. I think, sometimes, I'm a little too coachable," Duffy told reporters. "I'll just try to get my game right and back to where it usually is."

Of his talk with management, he said: "There was definitely some stuff I needed to get off my chest. I think it was a good talk ... long overdue."

Edwards, 29, was recalled for a second time this season. He was 2 for 7 in six appearances a month ago, and he was batting .171 with one home run in 51 at-bats for Indianapolis.