Belgian player in hospital after heart attack on field

Lokeren defender Gregory Mertens remains in hospital after collapsing during the early stages of his side's reserves match against Genk on Monday night (Tuesday AEST).

Lokeren's Gregory Mertens is in a serious condition after collapsing on field (AAP) Source: Press Association

The 24-year-old lost consciousness in the first half and was initially attended to by both the Lokeren and the Genk medical staff before he was transported to a Genk hospital, where he stayed overnight.

A statement on Belgian Pro League club Lokeren's official website sporting.be, read: "During the reserves match between KRC Genk and KSC Lokeren, Gregory Mertens collapsed after 15 minutes.

"Our defender was immediately assisted by the medical teams of Sporting Lokeren and KRC Genk. He was transferred to the hospital in Genk."

Reports suggest a heart attack could have been the cause of Mertens' collapse, while he remains in hospital and his condition is currently being assessed.

Lokeren spokesman Herman Van de Putte told sporza.be: "His condition is very critical. Gregory is in a medically induced coma, his heart function has been taken over by a machine.

"The fate of Gregory is in the hands of the hospital. We hope for a miracle."

The club added on its Twitter account: "Sporting sympathises with family and friends of Gregory and hopes for a positive outcome."

Mertens began his senior career at Cercle Brugge in 2011 before he made the move to Lokeren during last January's winter transfer window.

The Belgian defender made his debut as a late substitute in a 3-0 Pro League victory over his former club on January 18, 2014 and has made 30 further appearances for the first team since, including three Europa League outings earlier this season.