NASHVILLE, Tenn. — Steve McNair can't hide his enthusiasm.

The Tennessee quarterback always has done exactly what his coaches asked for — whether it was making the safe pass, handing off the ball or having only two or three audibles to use per game.

Now the Titans have a new offensive coordinator in NFL rookie Norm Chow, and the 10-year veteran quarterback feels like his hands have been untied.

"We can do just about anything we want in this offense as far as being a quarterback and making changes. The only thing he asks is why we did that, and give him a good reason. I think that is something we haven't had in the past," McNair said.

"As a quarterback, that's the exciting part about being a quarterback. Being a leader, you have to have that leeway to where you can change plays and not just put yourself in a bind."

Chow is one of 13 changes at the offensive coordinator position in the NFL this season. He may be new to the league after 32 years in college, but the man who tutored Heisman Trophy winners Matt Leinart, Carson Palmer and Ty Detmer has one guiding principle: Use your talent.

"The guy's one of the best quarterbacks in the NFL," Chow said of McNair. "To tie him up and say he just has to do what we expect him to do, hey, the defense may not be cooperating and there may be something better ... why not?"

Titans coach Jeff Fisher didn't switch coordinators to juice up the offense. In five seasons under Mike Heimerdinger, the Titans ranked among the league's top-11 offenses in 2001, 2003 and 2004, and McNair shared the MVP award in 2003.

But Heimerdinger was lured away by the Jets for more money and the New York spotlight. The Jets were looking for someone to help Chad Pennington and Curtis Martin find the end zone more often after firing Paul Hackett because they scored only two touchdowns in four games against Pittsburgh and New England.

Three other coordinators, besides Heimerdinger, switched teams.

Ted Tollner left San Francisco when Dennis Erickson was fired and resurfaced in Detroit with Steve Mariucci, his former boss with the 49ers.

Scott Linehan left Minnesota to help new Miami coach Nick Saban put more passing into the offense. The Vikings ranked second, first and fourth in total yardage in Linehan's three seasons there.

Mike McCarthy's contract was up in New Orleans, so he joined Mike Nolan in bringing the West Coast offense back to San Francisco. Saints coach Jim Haslett replaced him by promoting quarterbacks coach Mike Sheppard to help simplify and speed up the offense.

Other teams wanted change.

Jacksonville ranked last in the AFC in scoring, prompting Jack Del Rio to fire Bill Musgrave and hire Carl Smith, who worked at Southern California with Chow. Chicago fired Terry Shea and brought back Ron Turner, who oversaw the offense in 1995 for then-coach Dave Wannstedt. Turner is the Bears' third offensive coordinator in as many seasons, and his mission is to improve a unit that ranked last in nearly every category.

Before Red McCombs sold the Vikings, Minnesota coach Mike Tice promoted Steve Loney to help run the offense while overseeing the offensive line. This is Loney's first such gig in the NFL after doing it in college for seven seasons at Minnesota and Iowa State from 1995-2001. He joined Tice's staff in 2002.

New England coach Bill Belichick hasn't replaced Charlie Weis, who left for Notre Dame. Belichick said he'll be responsible for play-calling in the end, as always.

The only former NFL head coach to move into an offensive coordinator's position this year is Jim Fassel in Baltimore. His main objective is to turn Kyle Boller into an efficient passer who can use the new options he has been provided: standout receiver Derrick Mason and first-round draft choice Mark Clayton.

Dennis Green didn't like the inconsistency in his Cardinals when they had the ball last year and replaced Alex Wood with Keith Rowen. And all the upheaval in Cleveland brought Maurice Carthon, a Bill Parcells disciple, onto the staff of new head coach Romeo Crennel — also a Parcells disciple.