It is all possible for Jigsaw to return Jigsaw also died at the end of Saw II He was shot several times inguries he has no sign of in Saw III Not to mention numerous other horror characters have died and returned Like Micheal Myers or Freddy Krueger This also doesnt rule out flashbacks prerecorded messages Jigsaw might have left or even a prequel movie In otherwords in all horror evil has a way of surviving that is if it keeps making money But since the page only says Bell will be returning and may or may not be reprising the role of Jigsaw we cant really speculate Still we shouldnt completely rule it out