San Diego ? Marty Schottenheimer might be down to one last chance to get the San Diego Chargers to the Super Bowl.

Three days after the talented Chargers melted down in a stunning 24-21 playoff loss to New England, team president Dean Spanos decided Wednesday that bringing Schottenheimer back for the final year of his contract gives San Diego its best chance to win.

Schottenheimer, though, declined the team’s offer of a one-year extension for 2008 worth $4.5 million, with a $1 million buyout.

The coach didn’t offer specific reasons, but they could have to do with the spiraling salaries given to other NFL head coaches and perhaps to his strained relationship with general manager A.J. Smith.

“Right now, I wasn’t comfortable accepting it,” said Schottenheimer, who will earn more than $3 million in 2007, the final year of an extension he received after the 2004 season.

Spanos said Schottenheimer didn’t give him a reason.

“I offered what I thought was a fair offer, and it was surely up to him to make the decision as to whether to accept it or not, and he chose not to, and I respect that entirely,” Spanos said.

With a regular-season record of 200-126-1 with Cleveland, Kansas City, Washington and San Diego, Schottenheimer is the most successful coach never to have reached the Super Bowl.