Bale's future has been the subject of continued speculation in recent years following a string of injury problems which have limited the Welshman to just 31 league starts over the past two seasons.
Manchester United have regularly been linked with a move for the 28-year-old, and Marca claims that Bale has now begun isolating himself from his teammates.
The report goes on to say that manager Zinedine Zidane is unhappy with Bale's attitude this season, having fallen behind the likes of Isco, Marco Asensio and Lucas Vazquez in the pecking order at the Bernabeu.
Bale has still managed to score 12 goals in 29 appearances this term - already more than he managed in the 2016-17 campaign - but Zidane is beginning to lose patience with him and is willing to cash in this summer.
The report also says that Cristiano Ronaldo has tried to reach out to Bale, only for the former Tottenham Hotspur man to ignore the five-time Ballon d'Or winner.