Marshall has quality starts in nine of his 12 appearances this season and has allowed more than two runs in a game just twice.
"You just want to go out and pitch and go deep into games and save some of the relievers," he said. "You just try to go out and have quality starts and keep the team in games."
The Cubs enjoy a rarity in baseball: three lefties in a starting rotation. And the southpaw Marshall uses that to his advantage when watching teammates Ted Lilly and Rich Hill on the mound.
"It helps me out," Marshall said. "When I see one of our lefties pitching against the same team I get to pitch against, I can take and pull some of the things from the way they've pitched. It's been working out well so far and I'm going to continue to do my part."
Moyer's longevity impresses Lou: The Phillies' starter on Wednesday, Jamie Moyer, has enjoyed a successful Major League career, but it wasn't until after a 1996 trade from Boston to Seattle, which was then managed by Lou Piniella, that Moyer's career took off at the age of 34.
Now 10 years and 159 wins later, Moyer is still getting out big league hitters as he approaches his 45th birthday in November.
"He's had a heck of a career," Piniella said of his former player. "And it's come later on in his baseball life.
"I gave him a chance [in '96]. I let him pitch. We got him from Boston in a trade. He came over and won himself a spot in the rotation and solidified it, and he's had a really nice run."
When asked by a reporter why Moyer's had so much success in the twilight of his career, Piniella didn't offer a complicated answer.
"I don't know," he said. "I don't have an answer for you. He doesn't throw particularly hard. He changes speed pretty well. He usually doesn't beat himself. If I were a left-handed pitcher, I would certainly look at Jamie Moyer and see what I can learn from him."
Ramirez rests: The Cubs' third baseman got the day off on Wednesday, despite Chicago facing the southpaw Moyer.
"We haven't been playing him day-night," Piniella said, "so we're going to give him tonight off and play him tomorrow."
Scoreboard watching: Most players on a team one game out of first place would be lying if they said they don't pay attention to what's going on with the team ahead of them in the standings. But while they may check the scoreboard on a nightly basis, Cubs players insist they don't dwell or worry about what the Brewers do.
"I don't pay attention to what they're doing," Cubs outfielder Jacque Jones said.
"Does Carl Lewis ever look behind him when he's running the 100?" Jones said. "No, because it slows him down. The more we concentrate on ourselves, the more we can take care of our business."
"I watch how Milwaukee's doing," Piniella said, "but I don't focus on Milwaukee. It doesn't do any good really. It's more fun watching more than anything. But you've got to watch your ballgame and you've got to play good in the games you play in, and that's what we focus on."
So did the skipper catch the end of Milwaukee's 13-inning win on Tuesday night after Chicago's win?
"No, I went home and watched a movie and went to bed," he said.
Up next: The Cubs wrap up the final game of this four-game series against the Phillies with a 1:20 p.m. CT start at Wrigley on Thursday afternoon. Chicago lefty Sean Marshall (5-4, 3.10) opposes Philly's Kyle Lohse (6-12, 4.58).