Barzagli out for at least a month
The 2006 World Cup-winner has yet to feature this season after sustaining the problem ahead of the new campaign.
Head coach Massimiliano Allegri has been patient with the defender's recovery, but Sunday's news comes as a further setback.
In a brief statement released on their official website, Juve confirmed that Barzagli had seen a specialist and was suffering from a stress fracture.
Barzagli will now suspend his planned recovery programme and will continue treatment and specific training for the next 30 days.
Juventus take on Roma at home on Sunday, before a break of almost two weeks due to the international fixtures.