Real Madrid sold Álvaro Morata for €18 million this summer, and this move ended up haunting Los Blancos as the striker scored Juventus' opening goal in the first leg of the Champions League Semifinals. Morata completed a good performance overall and Real Madrid missed a presence like him on the roster given Karim Benzema's injury.
Real could buy Morata back for €30 million this summer, and the exact same buyback option could be triggered next year for €35 million, according to AS. But there is more. That same report indicates that Real would be willing to give him a better contract than the one he has with Juve now.
Should Real Madrid get that deal done because of a single game? Benzema has proven to be good enough to start for Real, and while Morata is indeed a good prospect, he would be nowhere near the French's importance in the team right now.
Furthermore, he left Real Madrid because he wasn't getting relevant minutes. Morata has been quoted a couple of times saying that he did not understand Ancelotti's decision to drop him when things were going well for him, meaning that he could play down a Real Madrid return if Ancelotti stays as the coach.