The Seattle Seahawks signed Vikings receiver Nate Burleson to an offer sheet Friday for a seven-year contract worth up to $49 million, including $5.25 million guaranteed. Burleson caught 30 passes for 328 yards and one touchdown last season while bothered by multiple injuries. It was a disappointing season for Burleson, who had 1,006 yards receiving and nine touchdowns in 2004 and was expected to become the top target with Randy Moss traded to Oakland.