The Belgian looks set to pen a new deal at the Blues.
But Spanish expert Guillem Balague believes Courtois could add a transfer clause into his new deal.
"It could easily have been interpreted as a mid-season review.
“Only... Thibaut is intelligent, well read, knows what he wants (he doesn't hide that it's Real Madrid), and is aware that he is not the only candidate (David De Gea being the other).
“And he needed to take that step that they usually demand at the Santiago Bernabeu before making a signing."