Porto will find out next month if they will be allowed into next season's Champions League, UEFA have confirmed.
The Portuguese giants stormed to the SuperLiga title, but their achievement was overshadowed by a six-point deduction they received for attempting to bribe referees during the 2003/04 campaign.
Porto were 20 points ahead of nearest challengers Sporting Lisbon with one game remaining when the penalty was enforced so it did not stop them being crowned champions.
But the admission criteria for the Champions League states a club 'must not be or have been involved in any activity aimed at arranging or influencing the outcome of a match at national or international level'.
That could spell trouble for Porto, with UEFA admitting the situation was 'being looked at'.
'It's down to the Portuguese League (LPFP) first of all,' a UEFA spokesman said on Tuesday. 'We have to wait until they present us with a list of clubs requesting entry. Once UEFA get that list then we can make a decision.
'We'll look at the request, check that all points are okay, that they all adhere to the admission criteria and if they do then there's no problem. It's hypothetical at the moment to say if Porto would be banned, I can't comment on that.
'But it is something that is being looked at and it will be decided at the beginning of June. Whatever happens Porto will be allowed to appeal.'
AC Milan were initially banned from the 2006/07 Champions League following the Italian match-fixing scandal but were successful in their appeal and went on to participate in - and eventually win - the European title.
Porto have triumphed in Europe's premier club competition twice, in 2004 and 1987, and reached the last 16 this campaign before being knocked out by Schalke on penalties.
The LPFP claim that, having clinched their third successive title, Porto's name will be on the list they present to UEFA.
'Porto have already been punished by the League,' LPFP head of communications Ivo Caldeira said. 'And they decided not to appeal so the matter is sorted as far as we're concerned.
'We analysed everything and we decided to deduct six points because of their attempts at corruption. That was their punishment so if it was up to us we would allow them to play in the Champions League.
'The ball is now with UEFA.'
If Porto are kicked out of the competition Benfica, who finished fourth, would take their place.