As Filipe Luis has found out, a big price tag and good reputation does not guarantee you a place in the starting eleven.
Gary Cahill and John Terry are the best partnership in the league at the minute and will not be moved lightly.
Even when the starting choices are not available, Ivanovic could just as easily slip into the centre of defence, with Filipe Luis coming in to replace Azpilicueta who would shift to right back.
It would not make sense for Pique to leave one bench for another.