The 2006 World Cup winner has spent the last three years with the Major League Soccer outfit but has featured in just 15 of the club's 32 games this campaign.
Asked by Italian newspaper Gazzetta Dello Sport what his plans are when his contract comes to an end on December 31, the 38-year-old replied: "You just realise that the time has come.
"Every day you have physical problems, you cannot train as you like because you always have some stuff. At my age, that's enough.
"It's not that you can go on forever to 50. I'll do something else."
Pirlo has won six Serie A titles and the Champions League twice during a career which saw him turn out for the likes of Inter Milan, AC Milan and Juventus.