(Renton, WA)  --  Seattle Seahawks backup quarterback Tarvaris Jackson is reportedly planning to test the free-agent market.  Jackson, who is a former starting quarterback for the Seahawks, turned down more money to sign a one-year deal last year with Seattle.  But Jackson, who will become an unrestricted free agent next month, reportedly may not re-sign with the Seahawks before the free-agency period begins.