“Verratti left the Coverciano training camp (on Thursday) morning as he returned back to his team Paris Saint Germain to undergo medical checks,” FIGC said on its official website.
Goalkeeper Gianluigi Buffon is also doubtful with an elbow injury he sustained playing for Juventus in their 3-1 Champions League final defeat against Barcelona on Saturday.
Croatia lead Group H with 13 points from five games, two more than Italy and four ahead of third-placed Norway.
The match in the Adriatic resort of Split will be played behind closed doors after the Croatians were handed a one-match ban for repeated offences by their supporters.
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Croatian fans shouted racist chants during a 5-1 home win over Norway in March after twice halting play in a 1-1 draw against Italy in Milan last November, when they hurled flares on to the pitch.
(Writing by Zoran Milosavljevic in Belgrade; editing by Pritha Sarkar)
