The Argentine, who has been out of work for almost a year after being sacked by Spurs in November 2019, remains of interest to Manchester United and other top clubs, meaning the La Liga side would be punching well above their weight should they make any move off the back of that interest.
Current Athletic boss Gaizka Garitano is under increasing pressure after a sluggish start to the 2020/21 season.
“I always feel ready to get back involved in the game. I love football, it’s my job,” said the former Southampton boss.
“It’s not a stress when you are working, it’s not a stress to go into the training ground, it’s not a stress to prepare the game, it’s not a stress to compete.
“My hair is long, look. I hope to cut it when we start working again.
“I am looking forward again to being involved in the game.”