Dinamo Zagreb midfielder Arijan Ademi failed a drug test after their Champions League match against Arsenal last month and is under investigation by UEFA, the club said on Wednesday.
Arsenal manager Arsene Wenger still believes his side have a "strong chance" to qualify for the Champions League last 16 for a 16th consecutive season as the Premier League side and Croatian champions Dinamo Zagreb face a do-or-die contest.
The 24-year old central midfielder, who has made three international appearances for Macedonia, failed the test after Dinamo's 2-1 home win over Arsenal in their Group F opener on September 16. The Ademi ban was a second blow for Dinamo in quick succession after the club's chief executive Zdravko Mamic was arrested on Wednesday for player transfer irregularities.
Arsenal defender Laurent Koscielny has been 'deeply affected' by last week's Paris attacks and might not be in the right frame of mind to play in Saturday's Premier League game against West Bromwich Albion, manager Arsene Wenger has said.
Olympiakos Piraeus battled back from a two-goal deficit to earn a 2-2 home draw with last year's runners-up Tottenham Hotspur in their Champions League Group B opener.
A round-up of Thursday night's matches from the Euro 2020 qualifiers.
A round-up of Wednesday's league stage matches in the UEFA Champions League.
Photos from the Euro 2016 qualifying matches played on Sunday.