Replays showed the full-back's knee twisting as he went for a 50-50 ball with Leicester's Boubakary Soumare.
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Play was immediately called to a halt as the Republic of Ireland international received treatment from medics.
He was later taken off on a stretcher but was seen applauding the travelling Everton fans at the King Power Stadium as well as handing out instructions to teammates before leaving the field of play.
It came towards the end of a very eventful first half which saw Everton surrender an early lead in sloppy fashion.
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After Dominic Calvert-Lewin put the visitors ahead with a penalty Leicester hit back through Caglar Soyuncu's strike.
Jamie Vardy then put the Foxes in front after being played through by James Maddison, who intercepted Alex Iwobi's sloppy pass.
But Iwobi made amends on 54 minutes as his half-volley brought Sean Dyche's men on level terms.
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