Everton and Belgium striker Romelu Lukaku is among a number of footballers who have sent well-wishes to Gregory Mertens, who suffered a cardiac arrest while playing for Lokeren.
The 24-year-old is understood to be fighting for his life in Ziekenhuis Oost Limburg hospital after collapsing on the pitch during a Jupiler Pro League match against Genk.
After hearing the news, Lukaku wrote on Twitter: "Keep fighting gregory!!"
Wolfsburg midfielder Kevin De Bruyne also took to social media to write, "incredibly bad news. Keep fighting Gregory," while Middlesbrough forward Jelle Vossen posted: "Be strong Gregory Mertens!!"
Mertens has made 15 league appearances for Lokeren this season.
