Real Madrid are reportedly looking to recoup more than £100m this summer through the sale of a number of loan players.
Los Blancos are expected to revamp their squad ahead of next season following a disastrous campaign this time around, culminating in the sacking of two managers and the reappointment of Zinedine Zidane.
Zidane is expected to be given around £300m to bring in new players, with Eder Militao already being snapped up from Porto, and Elconfidencial claims that a large part of that sum will come through sales of the current squad.
One member of the Madrid roster currently out on loan is Kovacic, who has spent the last seven months in the Premier League with Chelsea.
The report suggests that, should Chelsea wish to make that move permanent in the summer, they will have to hand over £42m