Colm Whelan is awaiting a specialist's report amid fears of another ACL setback.
The Derry City striker was injured in Monday’s defeat to Shamrock Rovers, only his third game back from a 10-month layoff.
Whelan had ruptured his cruciate last May while at UCD but returned and scored on his Candystripes debut away to Cork City two weeks ago.
And the 22-year-old then followed it up with another goal in a home win over St Patrick's Athletic.
It is understood that initial scan results this week - on the same knee he injured before - are a cause for concern.
Derry City are nervously awaiting a detailed breakdown from a specialist before they know the full extent of the problem.
READ NEXT:
Paul O'Connell gives his view on Ireland's position ahead of the Rugby World Cup
Conor McGregor told he went "too far" with comments about Khabib Nurmagomedov's dead father
Former Ireland international wants to Shine a light on mental health in sport
Kerry's Jason Foley not looking back after choosing football over athletics
Erling Haaland breaks Premier League record in first season to make history
Get the latest sports headlines straight to your inbox by signing up for free email alerts
