Keane was carried off on a stretcher in stoppage time of the 2-2 Premier League draw at Bournemouth and taken to hospital following a nasty clash of heads with team-mate Idrissa Gueye.
Everton on Sunday released a statement which said the 25-year-old had suffered the hairline fracture but “no other complications” and “will be unable to engage in head contact for between three and four weeks, from which point he will be able to resume full training”.
Keane was admitted to Poole Hospital, accompanied by club doctor Dr Aboul Shaheir, before being released on Sunday morning.
The former Burnley player, who had scored his side’s second goal against the Cherries, said: “Thank you to everyone for all the well wishes and support.”
© Agence France-Presse