Possible Clues:

• Illegal position on soccer field
• That's foul enough to have come from the flank
• Coming from the flank it must be absolutely foul
• Not on edge for the fowl, by the sound of it
• Away team is ahead of the ball
• What a foul way to be just not on the end of 20 across!
• What a foul thing for the eleven to do, but not enough to have them all on edge (7)
• In a position where ball can't be played (football)
• Bad team illegally ahead
• Dies off in illegal soccer position