"We needed to try a different approach," Piniella said. "We've been very patient, if you want to use that word. We've lost some tough, tough ballgames. Marmol deserves an opportunity, so we're going to give him that chance."
"I don't blame them," Gregg said. "We have to go with the hot hand right now. That's the life of my job."
Gregg served up a game-tying RBI double to San Diego's Chase Headley in the ninth inning on Monday and then a three-run walk-off homer to Kyle Banks as the Padres rallied for a 4-1 win. It was the 12th homer off Gregg this season, most among Major League relievers. He gave up three homers in 72 games last season.
"He understood," Piniella said of Gregg, acquired from the Marlins this offseason for Minor League pitcher Jose Ceda to replace Kerry Wood.
"He's a realistic young man," Piniella said. "This wasn't something that just cropped up overnight. That's a tough job for anybody and he's had some success, obviously, but lately he's been struggling. We decided to make a change and hopefully it works out best for our ballclub."
This spring, Gregg and Marmol competed for the job, but it was handed to Gregg, who had saved 61 games the past two seasons with Florida.
"We told [Gregg] basically that we were going to go in a different direction, closing-wise, and told him he could help us in the setup role," Piniella said. "[This will] take the burden off him a little bit and he'll be able to relax a little. [We told him] he was very important in those roles and he could help us win."
Piniella said he could also call upon John Grabow or Angel Guzman in save situations if needed. How long will Piniella stick with Marmol?
"No timetable," the Cubs manager said.
Marmol did sub for Wood last season, and has some experience as the closer.
"It's a natural progression," Piniella said. "Obviously, he has the stuff to do it. He's got the toughness to do it. It's just a question of getting the ball over the plate."
Marmol has had problems with his control. The right-hander walked 41 in 87 1/3 innings over 82 games last year, and issued 42 free passes in 46 games in the first half alone this year.
"I'll pitch whatever innings they ask me to," Marmol said. "We'll see what's going to happen. They made a decision, and away we go."
Gregg gave up game-winning home runs in back-to-back games in Florida Aug. 1-2, and also took the loss on Aug. 11 when Philadelphia's Ben Francisco hit the go-ahead blast in the 12th.
"To me, I'm getting beat now with the home run," Gregg said. "I just looked it up on the computer and I've given up more [home runs] this year than I did extra-base hits last year. That's kind of discouraging. That's the volatility of the closer. I've pitched pretty good all year and I've had three bad games in August here."
He doesn't count the game against the Phillies.
"It was a good pitch [to Francisco], and the sequence was right, and sometimes you just have to tip your cap," Gregg said.
There was some talk that Gregg was possibly tipping his pitches, which could be what's contributing to the home runs.
"I think I've gotten away from pitching the way I normally do," Gregg said. "I'm not going to throw 100 mph. It's not like I throw 85 [mph] up there. But I do more good sequences and I haven't done that lately. I don't know if thinking about tipping pitches has taken away from my concentration about what I'm trying to do to the hitter. I've got to get it back to together and get things going."
Did he sleep last night?
"No," Gregg said. "The biggest thing is I hate to lose. For me, personally, I'll take my bumps and bruises as long as the team doesn't lose. When the team loses, that's what really upsets me more. Now is not the time of year you want to be losing games."
Monday's Cubs loss, coupled with the Cardinals' win over the Dodgers, helped the St. Louis open a six-game lead in the National League Central. Gregg can't afford to make mistakes now.
"He's got to make better pitches, obviously, and I think he needs to pitch inside a little more just to make the hitter honest," Piniella said of Gregg, who did have a side session with Rothschild prior to Tuesday's game. "I feel that it's something that we needed to do, and hopefully it works well and gives our team a lot of life. We'll see."
Gregg says the problem has only been over the past few days, not the entire season. In the first half, he was 3-2 with 16 saves and three blown saves in 42 games, compiling a 3.32 ERA. In 16 games in the second half, the right-hander is 1-3 with seven saves and three blown saves, but has a 7.47 ERA. He's given up 15 runs and walked seven in 15 2/3 innings in the second half.
In eight games this month, Gregg has a 1-3 record with two saves, three blown saves, and an 11.25 ERA. He's given up 10 hits and walked two in eight innings.
"It happens to guys, they get in funks," said Gregg, pointing to Philadelphia's Brad Lidge as an example. "I've got to get right and do what I can to help the team."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.