Randall didn't get the start at home for Senior Day. Saban isn't worried about sentimental things, he's worried about winning. If starting Jamarcus Russell gives us the best chance to win, then Saban will start Jamarcus.
I don't think Saban wanted to start Russell in a road game after the Florida debacle ... that's why he started Randall against Arkansas. IMO, Randall gets the nod based on his performance last game and because it's not in Tiger Stadium.