MILWAUKEE — Jeff Samardzija refuses to sing.

He's not playing football at Notre Dame anymore, where it was standard practice to belt out the old fight song. Now, the Cubs rookie reliever will let his fastball hum and whistle for him.

"I will never sing in karaoke or anything like that," he said. "I know my limits."

The 23-year-old righty who grew up in Valparaiso, Ind. — smack dab between South Bend and Chicago — is already gaining staunch support with chants of "Let's Go Irish" echoing in Wrigley Field for the team with the NL's best record.

Not bad for just two appearances last weekend, which included his first save on Sunday.

"I know Chicago is a big Notre Dame town, so going to school there, I knew there would be a lot of common ground," he said. "The first couple of pitches were a little wild, but after that I kind of settled down and it was pretty fun."

Yes, Samardzija was nervous on Friday, but he looked confident and fired up in Sunday's two shutout innings to preserve a 9-6 win over Florida. He closed out a 7-1 victory last night at Milwaukee, allowing one run in the ninth and helping Chicago improve to 63-44.

"This is definitely how you write it up," he said. "If there's one time you'd want to be joining a team and be helping the team out, it would definitely be now."

Samardzija's rapid rise to the pros could have just as easily been catching footballs in shoulder pads.

The two-sport star finished with a school-record 179 receptions for 2,593 yards and 27 touchdowns at Notre Dame, and set single-season records for yards receiving and touchdowns.

But the wide receiver slipped to a fifth-round selection by the Cubs in the 2006 draft because of the uncertainty of him choosing baseball. The Cubs answered by giving him a $10 million, five-year contract in January 2007.

"I just really tried to be as aware and be as open-minded, like a sponge, as I could from Day 1 after showing up in spring training two years ago," he said. "Ever since then, it's just kind of been a learning process for me. Over the last month and a half, two months, things have started to come together."

That coming together includes cutting down his walks and working on getting ahead of hitters. While the Cubs project the 6-foot-5 pitcher to be a top starter one day, he's filling a bullpen role down the stretch with closer Kerry Wood on the disabled list.

"He's definitely a boost. Anybody you can add to the bullpen to get quality innings and get quality outs near the end of the game is going to benefit a team," Chicago reliever Neal Cotts said. "Plus, with Kerry not available right now, it's going to really help us. We get him back and with Jeff still there, it's going to be a big asset."

Samardzija also has a handle on the bullpen bag. Being the youngest player, he's been meticulous about what each reliever wants in the sack of goodies he must haul around. He also puts in a few specialties to make it signature Samardzija.

"I like to add some of my own additions to it, you know, some nice treats, some Red Bulls, stuff like that," he said. "You're going to have probably four Red Bulls in there, probably two of every sunflower seeds from ranch to barbecue. Bob Howry likes gum. Scotty Eyre likes pumpkin seeds, you've got to know the ins and outs of it."

So his role in the bullpen hierarchy is solid, even if his pitching role is still in question.

"I don't really want to put anything on it, put a label on it or anything. I just want to let them know, the staff know and everyone, my arm feels good," Samardzija said. "I feel like I can give them some solid innings and after that it's whenever they call on it."

Cubs analyst Bob Brenly said Samardzija's deceptive movement on his pitches, which includes an upper-90s fastball, could give him an edge down the stretch.

"Most guys that throw that hard, it's a pretty true fastball. But, he's got nasty sinking motion on the heater," Brenly said.

Samardzija's early success also has been exciting for Cleveland Browns quarterback Brady Quinn, his former teammate and close friend.

Quinn was asked what the odds were that Samardzija would get his first career save before he threw his first touchdown pass in the NFL.

"I don't know," said the Browns backup, who played just one series as a rookie last season. "Is there a line on that in Vegas?"

But Quinn is thrilled to see Samardzija doing so well.

"I wish him the best," he said. "Hopefully, they'll go to the World Series and he'll be part of something special for them."

And if there was any doubt, Quinn said Samardzija would have made a big impact in pads, too, if he'd chosen a pro football career over baseball.

"He's such a great athlete," Quinn said. "He's one of those guys who has been blessed with a lot of athletic ability. He's got the right attitude and the right work ethic and whatever it was going to be he was going to make it work."