The Dutchman replaced Roberto Mancini before the season started, but was sacked after losing seven of his first 14 games in charge.
“When you change Coach in August it's difficult for everyone," the centre-back explained.
“For the club, the Coach and the fans. The arrival of De Boer was a shock, he didn't speak the language. We didn't work well in pre-season.
“It wasn't easy for a Coach to come in and put his ideas across.
“Stefano Pioli? He gave an idea of how to play, a mentality and rules to follow. He didn't turn anything upside down, just put good players on the pitch.
“You can see the results, the lads are doing very well with him.
“My future? I'm an Inter player, I leave the door open to anything. I've never closed a door, there's no problem."