A byproduct of winning in the NFL has always been losing the people who helped you win.

Eagles coach Andy Reid has learned to live with that fact, and he did so again yesterday when linebackers coach Steve Spagnuolo left Philadelphia to take the job of defensive coordinator with the NFC East rival New York Giants.

Spagnuolo, 47, had worked with the Eagles since Reid took over as head coach in 1999. He initially held the title of defensive assistant, then was in charge of the defensive backs from 2001 to '03 before becoming the linebackers coach in 2004 after Ron Rivera left to become the defensive coordinator with the Chicago Bears. He replaces Tim Lewis, who was fired as the Giants' defensive coordinator shortly after New York's playoff loss to the Eagles on Jan. 7.

After thanking Giants head coach Tom Coughlin for giving him the chance to be a defensive coordinator, Spagnuolo talked extensively about leaving the Eagles.

"I want to thank publicly Andy Reid, [Jeffrey] Lurie, Joe Banner and Jim Johnson," Spagnuolo said during a conference call. "That is one class, great organization. I'll miss them all."

Spagnuolo is the third assistant coach to leave Reid's staff to become an NFL coordinator with another team. The Eagles also lost Dave Toub, who became the Bears' special-teams coordinator in 2004.

Reid lost offensive coordinator Brad Childress last off-season when he became the Minnesota Vikings' head coach. Childress could be courting Eagles secondary coach Sean McDermott to be his defensive coordinator. Mike Tomlin spent last season as the Vikings' defensive coordinator but was named the head coach of the Steelers yesterday.

The Giants ranked 25th in yards allowed and 24th in points allowed this season, so Spagnuolo has his work cut out for him.

"When you're in the business I'm in, you aspire to be in certain positions, and coordinator was one that I wanted," Spagnuolo said. "There's only 32 of them in this league."

Spagnuolo said he had an emotional conversation with Eagles linebacker Jeremiah Trotter yesterday. "I was touched by it, I can tell you that," he said.

Reid, who is at the Senior Bowl in Mobile, Ala., this week, traditionally moves quickly when he loses a member of his staff. One in-house candidate is Mike Reed, a Wilmington native who has spent the last four seasons as a defensive assistant and quality control coach. He has assisted Spagnuolo in working with the Eagles' linebackers.

Garcia meets Jay. Eagles quarterback Jeff Garcia will be a guest on The Tonight Show With Jay Leno at 11:35 tonight on NBC10.

Contact staff writer Bob Brookover at 215-854-2577 or bbrookover@phillynews.com.