LOS ANGELES (AFP) - United States Olympic 110m hurdler Devon Allen faces several months on the sidelines, after suffering a knee injury during an American college football game, reports said Monday (Sept 19).

Allen, who finished fifth in the final of the 110m hurdles at last month's Rio Games, is reported to have suffered a torn anterior cruciate ligament (ACL).

Allen, a wide receiver for the University of Oregon, is unlikely to play again this season, several US media reports said.

The injury is a cruel blow for the talented 21-year-old, who in Rio talked about the possibility of pursuing a National Football League career while continuing to compete in elite track and field.

Allen injured his right ACL returning a kick-off in 2015 and missed the following track and field season.

However, he recovered from that injury to win a spot on the US Olympic team with a first-place finish at the national trials in Eugene in July.