FA rule 18a states that "each team participating in a match shall represent the full available strength of each competing club".

But the huge growth in leading clubs' first-team squads has meant the rule has rarely been enforced in recent seasons and sources told AFP Wednesday they did not expect any action to be taken against Liverpool.

That would leave the way open for Arsenal and Manchester United - assuming in United's case they beat Exeter in Wednesday's third round replay - to rest leading players from their fourth round FA Cup games which take place just three days before their crunch Premier League meeting at Highbury on February 1.

Liverpool though did appear to stretch the rules close to breaking point with the likes of youngsters David Raven, Darren Potter, John Welsh and Zak Whitbread in their team at Turf Moor.