WASHINGTON -- Zach Duke, the Pirates' top pitching prospect, will make his major-league debut Saturday in Milwaukee.

That is the day Oliver Perez would have made his next start, but he broke his left big toe kicking a laundry cart Sunday in St. Louis and will miss three to six weeks.

Management has said that the pitcher who takes Perez's spot Saturday would be the one who stays in the rotation at least until Perez's return.

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 Class AAA Indianapolis, where he led the International League in victories with a 12-3 record and 108 innings.

The Pirates also considered using recent recall Ian Snell, a right-hander who also spent much of this season starring in Indianapolis, but he will remain in the bullpen.