Chelsea's defensive problems have been well-documented this season.
But one man Mourinho has not given an extended period in that role might just be the one best suited to the position.
The Chelsea boss would do well to give the Serb a run in the middle, however.
Time after time, Luiz's inconsistency has let the Blues down, while Cahill has flattered to deceive far too often this season.
Ivanovic offers a solid defensive option - and one that is much better suited to playing centrally.
At right-back, the 29-year-old is not as attacking as Cesar Azpilicueta and struggles to contain wingers - a prime example being his failure to stop Oussama Assaidi cutting inside and scoring the winner for Stoke some weeks ago.
But, at centre-back, Ivanovic could provide the perfect partner to John Terry.
The reshuffle would also allow Azpilicueta to play in his favoured position - at right-back - with Ashley Cole given the chance to return at left-back.
Mourinho, moreover, would have nothing to lose, as he could revert Ivanovic to right-back if he did not succeed.
It would be better to try the option, though, as Mourinho's constant switching between Cahill and Luiz has come to no avail so far.
So Jose... just play Ivanovic at centre-back already!
image: © Ben Sutherland