METAIRIE, La. -- Sean Payton cannot envision the Saints taking the field next season without quarterback Drew Brees, who could opt for free agency this winter now that he's played out his six-year contract.

"I don't even know if stunned would be a strong enough word," Payton said Tuesday, referring to what his reaction would be if Brees left. "I don't see that happening."

Brees has thrown for more yards than any NFL quarterback since joining the Saints in 2006 and passed for an NFL record 5,476 yards this season, breaking Dan Marino's 27-year-old mark of 5,084.

The star quarterback was among a number of players who had already left town and were not available for comment on Tuesday, the first day Saints headquarters was opened to reporters since last weekend's upset loss to San Francisco in the divisional round of the playoffs.

However, Brees has already said he expected an extension with New Orleans to eventually be completed. The quarterback likely will command a salary in the range of $18 million per year, which would be commensurate to the level of pay for New England's Tom Brady and Indianapolis' Peyton Manning.

Receiver Lance Moore said he was already operating under the assumption Brees would be his quarterback in 2012.

"As important as he is not only to this team but this city, this whole area, you kind of have to do right by him and sign him to a long-term deal because he's earned that," Moore said. "Where would we be without Drew? You can't even fathom that."

Still, Payton acknowledged free agency will be challenging for him and general manager Mickey Loomis because other key players from the Saints' record-setting offense have expiring contracts, including Pro Bowl guard Carl Nicks and receivers Marques Colston and Robert Meachem.

The Saints gained an NFL record 7,474 offensive yards this season, easily eclipsing St. Louis' mark of 7,075, which had stood since 2000.

"This season, certainly, there are some real good players that potentially are free agents," Payton said. "Each year those are challenges and that's what makes it hard to win in our league. ... We'll look closely at it and try to be objective."

Other free agents include cornerback Tracy Porter, defensive tackles Aubrayo Franklin and Shaun Rogers, linebackers Jo-Lonn Dunbar and Ramon Humber, and reserve defensive ends Jeff Charleston and Turk McBride. Starting center Brian de La Puente, receiver Adrian Arrington and backup quarterback Chase Daniel are restricted free agents.