Obomanu registered career highs in receptions (30), receiving yards (494) and receiving touchdowns (4) in a breakout season.
The fifth-year wideout tallied five receptions for 43 yards in Seattle's upset win against the New Orleans Saints last weekend, despite dislocating his shoulder in the first quarter.
Obomanu emerged after Seattle parted ways with big-name veterans T.J. Houshmandzadeh and Deion Branch. Houshmandzadeh was released prior to the start of the season and Branch was traded to the New England Patriots after week four.
The Seahawks locked up wide receiver Mike Williams with a three-year extension last Monday.
Information from NFC West blogger Mike Sando was used in this report.