"I can't give them dry runs every night, so when I get one up, I try to get him into the ballgame," Piniella said Wednesday. "I don't want to get two guys warmed up and all of a sudden don't use either of them, or use one of the two. I have to be careful how we do this.
"Remember, I told [the media] in Spring Training that what I was looking for was one more pitcher to pitch late innings. That's my biggest concern with our bullpen, and so far, we haven't found that guy. Hopefully, we will."
The concern in the 10th inning on Tuesday was who would face switch-hitting Lance Berkman. Piniella picked lefty Neal Cotts, who had come in in the ninth with two on and none out and escaped the jam.
"Anytime you can get their third hitter, Berkman, to hit right-handed, you're doing yourself a favor," Piniella said. "He got a base hit, but if you look at his numbers, they tell you [to] make him hit right-handed as much as possible."
Berkman did single off Cotts, who was pulled in favor of Gregg. He got pinch-hitter Jason Michaels to fly out, then intentionally walked Miguel Tejada to load the bases. Jeff Keppinger delivered a broken-bat RBI single for the game-winner.
Gregg is Piniella's third closer in as many seasons with the Cubs. When he first took over the team, Ryan Dempster was the closer, then Kerry Wood.
Besides trying to find the right combination, Piniella also is trying to avoid overworking Marmol, who appeared in 82 games last season.
"I'd like to not [use him as much]," Piniella said. "We have six out of seven new bullpen positions here, and Marmol's the only pitcher we have who was here at this time last year. You've got to see what these guys can do, No. 1, and how to use them.
"In Spring Training, you've got a whole ton of pitchers, you've got a whole ton of players, but when the season starts and you're down to 25, you really have to look at it, like last night. I stayed here for an hour, hour and a half after the ballgame, just going over the game and what could've been done differently. That's how you learn about your team. When you win, you don't give it much thought."
It will take some time. Plus, two relievers, Luis Vizcaino and Rule 5 Draft pick David Patton, have yet to get in a game. Piniella has been trying to find what he called a "soft landing" for Patton, who has not pitched above the Class A level.
On Wednesday, lefty Sean Marshall, the Cubs' fifth starter, was in the 'pen if needed. Cotts, Gregg and Aaron Heilman have pitched in both games so far.
"When you're not scoring a lot of runs, you're going to be pitching a lot of people," Piniella said. "We'll find out here in the first two, three weeks of the season, and if we have to make adjustments, we will."