ORCHARD PARK, N.Y. — Receiver Lee Evans signed a four-year contract extension worth $37.25 million today in a deal that prevents the Buffalo Bills' star from becoming a free agent after this season.

Evans, who is guaranteed to make $18.25 million in the new deal that runs through 2012, earned a significant raise over the base salary of $2.25 million he'll make this season, the final year of the rookie contract he signed after the Bills selected him 13th overall in the 2004 draft out Wisconsin.

Re-signing Evans was considered the Bills' top priority this year, and negotiations began in April.

Evans had also expressed a desire to remain in Buffalo, where he has emerged as the team's top offensive player.

"I know he's very pleased to have this behind him and be a member of the Bills for five more years," Evans' agent Ben Dogra told The Associated Press.

It helped a little bit in negotiations that the Bills (4-0) are off to their best start in 16 years and have an opportunity to end an eight-year playoff drought, the longest in team history.

"He always believed this was going to be a good team," Dogra said. "He's very comfortable with the leadership at the top. And the winning this year was the icing on the cake."

Evans has enjoyed only one winning season in Buffalo, his first, when the Bills finished 9-7 but missed the playoffs with a season-ending loss to Pittsburgh.

Though he was eligible to become a free agent this offseason, the Bills had the option to retain Evans' rights for at least one more season by designating him their franchise player.

Evans was not immediately available for comment. The announcement was made hours after the Bills completed practice in preparation for Sunday's game at Arizona.

Evans is off to the hottest start of his career this season with 14 catches, a team-leading 332 yards receiving and one touchdown. He ranks second among AFC receivers in yards and has six catches of 25 yards or longer, tying Green Bay's Greg Jennings for most in the NFL.

Evans already ranks seventh on the Bills' career list with 4,059 yards receiving, and fifth with 30 career touchdowns receiving.