Tosun started only two league games for Everton this season before his loan move to Palace in January
Turkey international striker Cenk Tosun has returned to Everton for tests to discover the extent of a knee injury.
The 28-year-old joined Crystal Palace on loan for the rest of the season in January and has made five appearances for the Eagles, scoring once.
Palace have an option for a permanent deal but it is feared an injury in training could end Tosun's season.
Some reports also place doubt on his involvement at Euro 2020, with Turkey's first match on 12 June.
Tosun moved to Everton from Besiktas for £27m in January 2018.
Source: bbc.com