CLEARWATER, Fla. - Zach Duke might not have pitched himself into the Pittsburgh Pirates' rotation Friday night. He certainly didn't pitch himself out of it.

Duke, coming off one of the best minor league seasons ever by a Pirates prospect, may have significantly increased his chances of staying in the major-league camp by pitching five shutout innings in the Phillies' 7-6 victory Friday night.

The left-hander, who has yet to pitch above Double-A, gave up three hits and walked one in the best start by a Pirates starter this spring. He was the first to go five innings, and how he did so was what was most impressive.

"I didn't know what was going to happen, but I didn't expect this," Duke said. "This was very unexpected."

Duke was in trouble only once, with runners on first and third with one out in the third, but he struck out Jim Thome swinging before getting Mike Lieberthal on a routine fly to left. He walked leadoff batter Tomas Perez in the fifth, but retired the next three batters.

Both manager Lloyd McClendon and general manager Dave Littlefield would prefer the 21-year-old Duke start the season at Triple-A Indianapolis. But, so far, he has pitched as well or better than the other contenders for the No. 5 job: holdover Ryan Vogelsong (1-1, 4.66 ERA in 9

innings), left-hander Dave Williams (0-1, 5.00 ERA in nine innings) and former major leaguer Albie Lopez (0-0, 1.29 ERA in seven innings).

"He (Duke) has some impressive numbers, he shows a lot of poise," McClendon said. "We'll see how it plays out. We're running out of innings, and Dave and I will sit down and discuss whether he starts again."

As of Saturday, the Pirates have two weeks' worth of exhibition games left.

Duke has a 3.60 ERA in 10 innings, with the previous five innings coming in relief. That's why McClendon and Littlefield wanted him to make at least one start during his first major league camp, to see how he would respond in his more accustomed role of starter.

They had to like this, with Duke constantly keeping the Phillies off balance with his curveball, changeup and well-placed fastball, which rarely reaches above 93 miles per hour but is almost never out of the strike zone.

Duke had the best numbers of any minor-league pitcher last season, going a combined 16-5 with a 1.46 ERA at Class A Lynchburg and Double-A Altoona. What was especially impressive was his consistency; he allowed two or fewer earned runs in 25 of 26 starts, and gave up three runs in the one start he didn't.

Still, the Pirates are reluctant to rush a pitcher who is 31-14 with a 2.21 ERA in three minor-league seasons to the majors so quickly. And while Duke was hopeful of having a good spring, he wasn't counting on making the Pirates' opening day roster.

"But a kid like this one, either he's ready to pitch in the big leagues or not," McClendon said. "I don't buy into this 'he's too young' stuff."