Arsenal goalkeeper David Ospina was taken to hospital after collapsing midway through his loan club Napoli's Serie A match against Udinese on Sunday.
The 30-year-old fell to the turf two minutes before half-time, having suffered an earlier head injury in a clash with Udinese's Ignacio Pussetto.
Napoli coach Carlo Ancelotti later indicated that Ospina was recovering but would be kept in hospital for observation.
In quotes published on the club's official Twitter account, Ancelotti said: "[It is] nothing serious - they did the tests and they turned out negative. He will have to stay [in hospital] tonight."
Ospina is on a season-long loan in Naples and reports suggest he is poised to sign a full-time deal with the Italian club.
Udinese had pulled back from two goals down to level the match when Ospina was forced off. Later goals from Arkadiusz Milik and Dries Mertens gave Napoli a 4-2 win.