WASHINGTON -- Zach Duke is doing more than counting the hours until his Pirates debut tomorrow. He also is clicking away on his laptop to analyze all he can about the Milwaukee Brewers' lineup he will face.

"I'm trying to learn everything I can," he said by phone yesterday from Ottawa, where Class AAA Indianapolis was playing. "There's only so much you can tell, but a little research will help me before I can meet with Spin Williams and go over it in detail."

For those who know Duke, the behavior is typical. Some might be calling friends and family to gush. He is trying to figure out how to get a curveball past Carlos Lee.

"Oh, I'm excited, believe me," he added, with a laugh. "I've been working for this my whole life, and I'm very eager to get out there. I can't imagine how I'll feel in the first inning. At the same time, though, I know the way I want to pitch that day. I've got a great chance here."

The Pirates announced yesterday that Duke, their top pitching prospect, will be promoted tomorrow to replace Oliver Perez, who will miss three to six weeks because of a broken left big toe. Duke will join the team today, then get formally added to the 25-man roster tomorrow. Outfielder Nate McLouth will be returned to Indianapolis.

Duke, 22, is a left-hander with exceptional poise and control who nearly made the Pirates' roster out of spring training. He was assigned to Indianapolis for his first Class AAA experience, and he led the International League in victories with a 12-3 record and 108 innings. He had a 2.92 earned run average, 66 strikeouts and 23 walks.

"It doesn't surprise me one bit. And I really mean that," Pirates manager Lloyd McClendon said of Duke's showing. "I thought the kid was special coming out of spring training. I'm excited for him to be here. These are the types of guys you build around, that you get excited about. I'm excited for him to be coming here."

Duke expressed satisfaction with his performance.

"I think I did what I set out to do," he said. "I had to make some adjustments to some of the older hitters here, but that came with some time. I'll have to do the same thing when I get called up."

He has four pitches he uses consistently, but he did not hesitate in pointing to his fastball as his key, even though he is not a hard thrower.

"I have to pitch to my command, and that's the one that makes it all go. I have to be able to throw the fastball where I need to."

Management's decision came down to Duke and recent recall Ian Snell, both of whom excelled in Indianapolis. McClendon explained that the choice was "more a matter of starter vs. bullpen," and that Snell would remain a reliever because he had experience in the role.

North Side notches

Outfielder Craig Wilson will join the Pirates today in Milwaukee to take his first batting practice with the team since his left middle finger was injured May 6. If all goes well, he will begin a minor-league rehabilitation stint Monday. That likely would last a week or more, keeping him on track to rejoin the lineup after the All-Star break.

Second baseman Jose Castillo and catcher Humberto Cota were held out of the starting lineup yesterday after getting hurt Wednesday, but the team described both actions as precautionary. Castillo had no complications from an asthma attack that came with a headfirst slide into second. Cota, who was beaned just above the ear flap of his helmet, passed a concussion test yesterday morning.

Because Dave Williams' start Wednesday was reduced to two innings by rain, he will be available to pitch out of the bullpen tonight or tomorrow in an emergency.