Daniele De Rossi anxiously awaits test results, as he is an injury doubt to face Uruguay on Tuesday.
The Italy and Roma midfielder was spotted limping towards the team bus after a 1-0 defeat to Costa Rica in Recife.
“It isn’t a knock. We’ll see,” he told journalists, confirming the problem was in his left calf.
If this is a muscular strain, then De Rossi is unlikely to be fit in time for Tuesday’s decisive World Cup clash with Uruguay.
Italy need at least a point from that game in Natal to progress in the competition.
There are other injury concerns for the Azzurri, as defender Andrea Barzagli had already been in doubt to face Costa Rica.
He has suffered from persistent tendon problems this season and over the last month never played three games in a row for Juventus.
Giorgio Chiellini appeared to be exhausted in Recife, but Milan full-back Mattia De Sciglio is on the road to recovery after missing the first two matches with a thigh injury.
Claudio Marchisio also had a knock to the knee, but reassured journalists it was “nothing serious.”