Barzagli was forced to pull out of today's session and tests have since confirmed that the 27-year-old defender will require surgery after rupturing the meniscus in his left knee.
Though Barzagli was not expected to start against Spain in any case, Azzurri boss Roberto Donadoni now has scant cover for the centre-back position, with only Marco Materazzi and the unexperienced Alessandro Gamberini left to deputise for current first-choice pairing Christian Panucci and Giorgio Chiellini should the need arise.
The news is especially bitter for Bundesliga side VfL Wolfsburg, who had just completed the signing of the defender from Palermo weeks ago.
There is no word yet on how long Barzagli is expected to be out of commission for, but the recovery from even less severe knee meniscus injuries are measured in months rather than weeks.
Derek Wanner, Goal.com