Chris Cooley, the Washington Redskins' biggest potential free agent after this season, was taken off the market yesterday when he signed a six-year contract extension worth a maximum of $30 million. Cooley, 25, who is entering his fourth season as the starting tight end, will make $14 million in guarantees. He will earn $850,000 this season ? the last year of his current deal. "It feels so good," he said. "I feel this is such a great place for me and it's a great fit to be with the Redskins. I'll be here seven more years and I can play my whole career here and that's an unbelievable thing, especially in today's football."