The Pistons will open a four-game trip tonight in Portland. Detroit, now 2-and-3, is riding a 19-game winless streak in road games against Western Conference opponents. Charlie Villanueva(shoulder) was a full participant in Sunday’s practice and could play tonight. The Trail Blazers, now 4-and-2, seek their fifth win in six games. The Pistons will also face the Warriors, Kings and Lakers before coming home.