The Football Association (FA) is examining a yellow card received by an Arsenal player linked to suspicious betting patterns during a Premier League match this season.
Sources have to ESPN that bookmakers have alerted the FA to unusual amounts of money being staked on a member of Mikel Arteta's team to be booked.
An FA spokesperson said: "The FA is aware of the matter in question and is looking into it."
Arsenal are understood to be aware of the situation. The player has not yet been named publicly and a formal investigation has not yet been opened.
It is understood that the FA's enquiries are initially focusing on betting patterns rather than any individual player's conduct.
The growth in the volume of gambling markets has led to what is known as "spot betting" where the possibility of highly specific incidents including the time of a card, corner or throw-in can be wagered on.
Instances of spot-fixing in Premier League football are thought to have been extremely rare, not least because of the huge wages players earn.
However, the UK government has been examining the relationship between the sport and the betting sector, with the Department for Culture, Media and Sport expected to publish a white paper on a wide-ranging review of gambling laws early this year.