Cubs call up top pitching prospect Cashner

The Cubs wasted no time getting their top pitching prospect on the roster for a road trip the team considers critical.

Or getting him his major-league debut.

Hard-throwing right-hander Andrew Cashner was recalled from AAA Iowa today to join the Cubs’ bullpen for today’s series opener against the Pittsburgh Pirates — and made his one-pitch debut just four hours after his plane landed in Pittsburgh.

Cashner, the Cubs’ first-round draft pick in 2008, entered the eighth inning with two out and two on to face former Cub Ronny Cedeno with the Cubs trailing 2-1.

He threw a 95-mph fastball that Cedeno popped to short to end the inning.

Making room on the roster for Cashner, struggling reliever John Grabow was placed on the 15-day disabled list today because of inflammation in his left knee. Grabow, who is 0-3 with a 9.45 ERA, had a cortisone shot in the knee in recent weeks but continued to struggle.

Cashner was moved into the Iowa bullpen Thursday in anticipation of a possible callup this week.

“We’re going to use him in the middle just to get him started, get his feet wet,” manager Lou Piniella said, “and hopefully he’ll develop into a nice later-inning pitcher for us in the bullpen.”

The manager said he might not wait long if the former Texas Christian closer adapts quickly to the big-league role.

“Basically, we’re hoping that he just takes Zambrano’s spot the way we were using Zambrano,” Piniella said.