Supporters were left questioning his physical state, with the 28-year-old looking podgy and scruffy in training pics.
The Spaniard appeared a long way from the fit athlete he was a few years ago, when he was regarded as one of the best midfielders in the world.
Isco has been limited to only 148 minutes of on-field action this season and fans are concerned they may not see much more of him in the near future.
His manager, Zinedine Zidane, when asked about the midfielder after Madrid lost to Cadiz last week, mostly sidestepped the question.
He said: “We are all in the same boat and criticism makes us stronger. We know we are Madrid and there is criticism after a game like the one the other day.
“We can only get back to work. The good thing is that there is a game every three days. We deserved the criticism the other day, and me before anyone – not just the players, they fight.
“We want to change the dynamics. I have no doubts about anything.
“The other day was a bad day, we want to change things, Isco more than anyone, I have no doubts.”