Pastore is now impressing in coach Paulo Fonseca's midfield.
"During that period [the summer] I spoke a lot with the coach and his staff," he told the club's official website.
"I was able to get up speech physically by playing in all the friendlies, although in one week we decided to stop playing together, it wasn't an injury, but after double sessions every day, and knowing my body well, I asked for a break."
"I asked the coach to leave me out of some friendlies, so that I wouldn't pick up injuries early in the season, he accepted that, and told me to train all week, and to be ready for the first game of the season."
He continued: "I've been booed at every team I've played for, just as I've been cheered too. It's because of the way I play, if I am fit and well I can contribute, but If I can't physically then I can't give my best. If you don't have to strength to run back, the fans notice that.
"Sometimes I appreciated the boos. When things are going well it's clear, when things are going badly you need that reaction from the fans. It's the sort of thing that personally gives me a bit of a kick."