Gregg saved 61 games during the past two seasons for the Marlins.
"I love it," Gregg said of his new environment. "The fans are into the game. There's an intensity in the air that you can't explain.
"I went from [Los Angeles] to a team in Florida [where], frankly, the fan support wasn't there, and to come back to it, it's such a good feeling, to be a part of something that everyone believes in."
Gregg is still the closer, but Marmol will again be allowed to convert save opportunities. That may complicate things for your fantasy baseball team, but Cubs manager Lou Piniella is pleased with the arrangement.
Gregg appeared in five of Chicago's first seven games, but hadn't been used since Monday, when he struck out three Rockies in the ninth inning of a 4-0 victory. The Cubs have monitored Gregg, who underwent surgery on his left knee during the offseason.
They're trying to avoid Gregg warming up multiple times and aggravating his knee. If Marmol is throwing in the bullpen, chances are Gregg will be sitting. That situation could be fluid. Eventually, Piniella expects Gregg to warm up more than once in a game.
"We'd like to stay away from that if we can, but I would say that once the weather starts warming up, the answer is yes," Piniella said before Saturday's game. "It's early in the season here. I don't want to get caught warming both of them up and using one and not using the other. I have my reasons for that. But [if] we get to a save situation today, Gregg will have the ball."
For his part, Gregg met with Piniella before Saturday's game: "I had four days off and I told them, 'If you need me for two, I got that in the tank.'"
And that's exactly what he delivered. When asked before the game if Gregg was fine physically, Piniella had a quip ready.
"He's better than me," the manager joked. "Yeah, he's fine."
But Gregg's results Saturday -- no hits in two scoreless innings -- were more convincing.