Isco has been in and out of Zidane's starting line-up this season, prompting links with a move to Camp Nou.
The 24-year-old did himself no favours in terms of attracting attention to what would be an explosive switch by posting a picture of a meal with friends, where a packet of Barcelona-branded potato chips were clearly visible on the table.
Realising his error, Isco reposted without the offending item and later tweeted to say he was not going to Barcelona, with the added assurance that he had not sampled the savoury snack.
"There's no controversy about the potato chips, we are just thinking about the game tomorrow," a grinning Zidane said ahead of Saturday's Madrid derby against Atletico – a crunch clash the European champions enter with a two-point lead over Barca at the Liga summit.
"We know that all of this [speculation] is part of football - everything that's said and written off the pitch.
"We are only interested in what's going on on the pitch and what we're going to do."
Que no me voy al barça pesados!! Con la foto queria decir que nos lo vamos a comer con patatas #HalaMadrid!!— ISCO ALARCON (@isco_alarcon) April 6, 2017
Another playmaker whose Madrid future was thrown into question once more this week, albeit in more conventional circumstances, was James Rodriguez.
He appeared to swear at Zidane when trudging off to make way for Isco and went on to punch the dugout after ignoring his coach on the touchline.
Zidane sympathised with James' frustration after the match and was unwilling to reopen the issue before facing Atletico.
"Yes of course, it’s not a controversy," he said. "It's what happens with a manager, it happens in football.
"James, I – we all have the same interest. You think we're going to speak more about this? No, it's all in the past and that's it. We're thinking about tomorrow."