"You just come to realise that the time has come", he told La Gazzetta dello Sport. Each day, you have physical problems and you can't train as you would like to because there's always some niggle.
The 38-year-old will retire at the end of the current MLS season, and in doing so will bring the curtain down on a stellar playing career that has seen him win numerous game's top competitions. At my age, it's fine to say enough is enough. You do not have to continue like this until you are 50 years old, no. I will do something else. "I'm not angry. Instead, I will give a hand to team-mates and to the coach".
Chelsea manager Antonio Conte is one of the best managers in world football, according to Andrea Pirlo. "It wasn't just that I wanted to come back to Italy, but AC Milan is a legendary club and they had a great team". I have my ideas, but I will allow myself time to decide.
Pirlo, who began his career with Brescia, won Serie A and the Champions League twice among a host of honours with Milan.
He has been playing professionally since 1994-95.
Pirlo played under the likes of Giovanni Trapattoni, Marcello Lippi and Cesare Prandelli during his stellar global career, but the man with 116 caps to his name picked out one former boss for special praise: Antonio Conte.
"It's hard to build a new team, it takes time and faith and you know results won't arrive straight away".
Italian legend Andrea Pirlo bid farewell to a glittering football career that spanned more than two decades, 22 years to be precise.
Conte will now hope that he can prove himself once more this season, as he looks to retain the Premier League title with the Blues.