NEW YORK -- His baseball home for more than three years, Billy Wagner is back in New York City as a visitor this weekend. Not only that, but the left-handed reliever will get his official initiation into the Red Sox-Yankees rivalry.

While Wagner played against the Yankees plenty of times during the Interleague showdowns when he was with the Mets, he could say before Friday's game even started that it wasn't at the same level as what he is getting into.

"No," said Wagner. "Two different divisions. That really has no bearing on whether you win your division or not. When you played that, it was more for the city and the fans. This is in your division, it's a rival. You approach it a little different."

An avid college football follower, Wagner loves a good rivalry.

"I've played in rivalries and stuff like that, but this is definitely the biggest one," Wagner said. "You just approach it like you've approached everything else. Try not to make too much of it and try not to get caught up in everything that's going on."

Because Wagner was on the disabled list when the Mets played at Yankee Stadium earlier this season, this was his first trip to the new venue.

"I don't think you can replace the experience of the old Yankee Stadium and the tradition," Wagner said. "It's a sad thing when they had to upgrade and make adjustments. But walking out there, seeing the monuments and stuff, I enjoyed that."

And now, Wagner is enjoying his new line of work, as a luxury item in a loaded Boston bullpen.

"About as easy as can be," said Wagner. "You've got a stacked bullpen, and I just kind of come in when they need somebody to throw an inning, so it doesn't get much easier than that."

The Red Sox have yet to pitch him on back-to-back days, mindful of the fact he is still just one year removed from Tommy John reconstructive surgery on his elbow.

With Boston now on the verge of clinching a postseason berth, manager Terry Francona probably won't pitch Wagner back-to-back until the American League Division Series, if even then.

"The way this bullpen is stacked up, I don't know if the playoffs mean I'd go back to back," Wagner said. "I am looking forward to going back to back if they need me to go back to back. They're very talented. Whatever they need me to do, I'll be happy to do."

Since joining the Red Sox, Wagner has a 2.61 ERA in 11 innings. Over 10 1/3 innings, he has five walks and 16 strikeouts.

How does Wagner think his stuff compares to pre-surgery?

"Pretty much like the same, but I'm not sure where it's going all the time," Wagner said. "That's not always a bad thing."