NEW YORK (CBSNewYork/AP) — Mike Pettine intends to bring his aggressive approach to Buffalo in a bid to transform the Bills’ high-priced, yet underachieving defense.

Pettine is taking over as the Bills defensive coordinator, leaving the Jets after four years with coach Rex Ryan.

New Bills coach Doug Marrone went with Pettine, based on the attacking style of defense he ran during his previous four seasons as New York’s coordinator.

“His defenses are known for their relentless attacking style,” Marrone said. “That’s exactly how I envisioned our defense.”

The moves were announced three days after Marrone took over in Buffalo, replacing Chan Gailey who was fired after three consecutive losing seasons.

Pettine has 12 seasons of NFL experience, having also worked as a defensive coach at Baltimore. He was available after turning down New York’s offer to extend his contract last season.

In wishing Pettine well earlier this week, Ryan kidded that he hoped his assistant would wind up anywhere but Buffalo, New York’s AFC East rival.

“Rex and I are like brothers, brothers that fight a lot,” Pettine said, noting he watched Ryan’s news conference and heard his comments. And yet Pettine still picked Buffalo.

“I love Rex, and am so thankful for the opportunity I had there,” he said.

Pettine insisted that his relationship with Ryan remained strong.

“Much had been made of the relationship and how things had soured, and that’s not the case at all,” he said. “It’s the exact opposite. Our relationship is as strong as it’s been. We both felt it was time for me to explore new opportunities and step out from under his shadow and move on.”

Under Pettine, New York’s defense has not ranked lower than eighth in the NFL in yards allowed. And that includes a top ranking in 2009.

He takes over a Buffalo defense that last season finished 22nd in yards allowed, while giving up 435 points — the second most in team history.

Pettine is accustomed to a three-lineman, four-linebacker formation, while the Bills went with a 4-3 look last season. He intends to go with both formations, and fit them to the strengths of his players.

Which defense will be better next season — Jets or Bills? Be heard in the comments!

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)

Watch & Listen LIVE