PITTSBURGH -- The Cubs started Mike Fontenot at second base in place of Ryan Theriot in the opening game of the three-game series in Pittsburgh. Cubs manager Lou Piniella hinted that it may be more than just a spot start.

"Fontenot has had a good month," Piniella stated. "He's swinging the bat well. We'll see how Fontenot does, but this could be more than a one day thing."

Fontenot entered play on Monday batting .337 with one home run and 15 RBIs. Theriot was hitting .286 with no home runs and 14 RBIs.

"Fontenot is swinging the bat and putting the ball in play," Piniella said. "He's been better. With Theriot, he's had one walk the whole month. That's kind of hard to do. We've talked to him about it and he's had one extra-base hit the whole month, but we'll see. We'll see what happens, but I've got to start getting people in there that are swinging the bats the best."

Fontenot went 0-for-4 in the 2-1 loss to the Pirates. Theriot entered the game as a defensive replacement in the eighth inning and then struck out against Octavio Dotel for the game's final out.

Grabow placed on DL

PITTSBURGH -- The Chicago Cubs placed lefty reliever John Grabow on the 15-day disabled list with inflammation in his left knee on Monday. Grabow has appeared in 23 games and has a 0-3 record with a 9.45 ERA.

"I'm going to try and give myself a little time and let it rest," Grabow said. "I'm going to work on some things and get freshened up and help later on."

Grabow has struggled out of the bullpen. He already has lost his primary setup role and had been relegated to mopup duty, despite being in the first year of a two-year, $7.5 million deal.

"It is a sprained left knee," Grabow reported. "The same thing as before. I'm just going to let it calm down and get it right and obviously I'm not pitching the way I should be pitching and I want to get it right."

The Cubs selected the contract of right-hander Andrew Cashner from Triple-A Iowa.

"We DL'ed Grabow," manager Lou Piniella explained. "He's got the inflammation in the knee and he'll get a chance when he's OK to work with pitching coach Larry Rothschild a little bit and hopefully he can get going. We need for him to pitch better. He's been getting the ball up and he's been getting hit."

Cashner debuts out of bullpen

PITTSBURGH -- Right-hander Andrew Cashner came up from Triple-A Iowa on Monday. Cashner was moved from the rotation to the bullpen at Iowa late last week, and he pitched twice in relief. Cashner, a closer at Texas Christian University, was the Cubs' first-round Draft pick in 2008.

"He's a good young arm," Cubs manager Lou Piniella said. "We had him at Spring Training and he went down to Double-A and started and at Triple-A; he's started at both classifications. We're going to put him in the middle just to get him started and get his feet wet and hopefully he'll develop into a nice late-inning pitcher for us in the bullpen.

"Basically we're hoping that he can just take Carlos Zambrano's spot, the way we were using Zambrano."

Cashner made his Major League debut in the eighth inning of Monday's 2-1 loss to the Pirates. The right-hander needed just one pitch to retire Ronny Cedeno on a popup to shortstop to end the eighth inning.

"I was a little nervous out there today," Cashner admitted. "I was able to control things and make a pitch."

Gorzelanny moving to the 'pen

PITTSBURGH -- Left-hander Tom Gorzelanny is the odd-man out of the starting rotation with the return of Carlos Zambrano on Wednesday at Pittsburgh. Zambrano rejoins the rotation after slightly more than a month as a setup man. Gorzelanny is 2-5 with a 3.66 ERA.

"Gorzelanny had a throw day on Saturday," Cubs manager Lou Piniella indicated. "We didn't use him [Sunday], but he's ready to go today and he's in the bullpen and he'll pitch in the middle to long role to start with and we'll see how he goes."

Gorzelanny expressed a preference to stay in the rotation, but will do whatever it takes to help the team.

"Whatever they need me to do is what I'm going to do," Gorzelanny said. "I felt like I've pitched well and look forward to continuing to do that now. Whatever they need me to do I'll be able to do."