The highly-rated central midfielder was linked with Liverpool, United and Barcelona last week, and the latest report claims the Spain under-21 star could be snapped up for a fee around his €20m release clause.
Because Atletico would be powerless to stop the likes of Liverpool or United talking to Koke if they triggered the release clause.
He's been dubbed the 'new Xavi' in Spain, and while he's under contract in the Spanish capital under 2018, he's believed to be a target for some of Europe's biggest clubs.
Barcelona have an obvious interest - if there's one player to replace the 33-year-old Xavi, then the 21-year-old 'new Xavi' wouldn't be a bad place to start.
Koke already has three caps for the Spanish national team, and is hoping to be named in Vicente Del Bosque's squad for next summer's World Cup.
He's been an integral part of a successful Atletico team this season - the club currently sit level on points with Barcelona at the top of the La Liga table with eight wins from as many games.
Koke has featured in every league match, and already has two goals and a league-best six assists.
Manchester United were interested in several of Spain's top midfielders this summer, including Ander Herrera, Thiago Alcantara and Cesc Fabregas.
But ultimately David Moyes came up empty-handed and the Old Trafford boss signed Marouane Fellaini from Everton instead.