Mike Pettine's dilemma: 3-4 or 4-3 defense?

The Buffalo Bills hired former New York Jets defensive coordinator Mike Pettine for the same position, ESPN's Chris Mortensen reports.

This is a great hire for the Bills as long as they can correctly answer one question: Will Pettine run his 3-4 defense in Buffalo or keep the Bills in a 4-3 scheme?

Pettine spent four seasons in New York running an aggressive and successful 3-4 defense along with Jets head coach Rex Ryan. The Jets just began adding more 4-3 looks into their playbook in 2012, but certainly not enough to be deemed a 4-3 team.

The Bills were an unsuccessful 3-4 defense until switching last year to better fit their personnel. Buffalo acquired pass-rushing defensive end Mario Williams for $100 million in free agency to cement the move. The Bills' defensive line, highlighted by Williams and defensive tackles Kyle Williams and Marcell Dareus, looked tailor-made to run a 4-3 defense. But the group terribly underachieved under former defensive coordinator Dave Wannstedt.

That brings us back to Pettine. Will he implement his 3-4 scheme and make the players fit into it? Or will Pettine alter his scheme and philosophy and run a 4-3 defense that will fit his players? That is a tough question for Pettine.

What I do know is the Bills do not want to upset Williams, who is their most expensive player. Williams bickered in Houston because the team changed to a 3-4 defense, which required him to stand up as an outside linebacker. Taking Williams out of his element again could make him uncomfortable, unhappy and less productive.

But at the same time, Pettine needs to do what made him most successful in New York. That's why the Bills hired him. It’s a rough dilemma that Pettine and the Bills must figure out sooner than later.