PITTSBURGH - Paul Maholm didn't wait long to get to the major leagues with the Pittsburgh Pirates. He must wait another day to make his debut.

Maholm, a 2003 first-round draft pick, was to have made his first start Monday against the Cincinnati Reds, but the afternoon game was rained out before it could begin. The game will be made up as part of a doubleheader Sept. 16, when the Reds play the Pirates for the third time in four weekends.

Maholm will become the seventh rookie to debut with the Pirates this season when he starts tonight in Milwaukee. Pirates manager Lloyd McClendon could have skipped over him because of the rainout, but instead will bump left-hander Dave Williams (10-10) from his scheduled start Tuesday and keep everyone else on schedule.

Maholm will at least temporarily replace unbeaten left-hander Zach Duke (6-0) in the rotation. Duke will miss at least two starts after spraining his left ankle running the bases Tuesday against St. Louis.

The left-handed Maholm missed most of last season after being struck in the face by a line drive May 15 while pitching for Class A Lynchburg. He needed two operations for a broken nose and some fractured orbital bones, but bounced back to go 6-2 at Double-A Altoona and 1-1 at Triple-A Indianapolis with a combined 3.30 ERA this season.

Maholm didn't expect to reach the majors this quickly, and with so little minor league experience, but he impressed McClendon during spring training.

"He's a strike thrower who knows how to pitch," McClendon said. "I liken him a lot to Duke in terms of poise. He's a great competitor and he won't be overwhelmed."

The 23-year-old Maholm was nervous Monday, but not just because of his planned debut. Maholm and his wife, Jessica, recently purchased a new home close to Biloxi, Miss., which was hit hard Monday by Hurricane Katrina.

"I guess I'll find out tomorrow if it's still there," Maholm said.

Maholm also was worried because his wife's parents chose to ride out the storm in Mississippi rather than move to a safer location.

Pirates rookie catcher Ryan Doumit would not have started for a second consecutive day Monday because of a concussion that occurred when he was struck in the mask by a foul ball Saturday. The third Pirates rookie to be injured within a week, Doumit could return as early as Tuesday.

Also hurt last week were Duke and center fielder Chris Duffy, who could miss the rest of the season with a torn left hamstring. Duffy was off to an excellent start in the majors, hitting .341 in 39 games and playing almost flawlessly in the field.

He didn't initially believe the injury was serious, but an MRI test revealed the tear and he was placed on the 15-day disabled list.

The Reds, on the verge of their first four-game sweep in Pittsburgh since 1992 before the rainout, will back up their pitchers a day. Ramon Ortiz (8-9), who was to have pitched Monday, now starts Tuesday night in Houston, with Brandon Claussen (9-8) going Wednesday and Aaron Harang (9-11) on Thursday.

Eric Milton (7-12) starts Friday in Atlanta, followed by Luke Hudson (6-6) and Ortiz.

The Reds have won four in a row and eight of 10, and have won 14 of their last 16 road games.

No wonder manager Jerry Narron said, "We definitely wanted to play" on Monday.