The 33-year-old has struggled to replicate his form of 2011-12 so far this season, and Boban believes that not playing for Italy will help him rediscover his form.
"I think that it's time for Pirlo to leave some duties behind," he told Sky Sport Italia. "He should retire from international football.
"He has been lacking the brilliance that he showed last year, and I think it may be down to the fact that he has too many commitments.
"He hasn't had much rest this summer."
Pirlo was instrumental in Juventus's Serie A triumph last season and also helped Italy reach the Euro 2012 final.