Premier League champions Manchester United could make a surprise comeback to this season's UEFA Champions League, after FIFA threatened to ban all Swiss teams from all football competitions. In response, UEFA have said they will consider a replacement, should FC Basel (who qualified for the knockout stages of this season's Champions League, at the expense of United) be prevented from playing further part.

The Swiss Football Association has been handed a deadline of Jan. 14, according to a Daily Record report, to follow FIFA's instructions on a registration ban similar to the one imposed on fellow Swiss club FC Sion.

Sion were punished, first, in 2009, when they illegally signed Egyptian goalkeeper Essam El-Hadary. The club qualified for this season's Europa League (the continent's second-tier club competition) by winning their domestic cup last season. However, following confusion over the period of punishment (which involved a transfer embargo), they fielded ineligible players in their Europa League play-off victory over Scottish club Celtic. As a result, they were disqualified from the competition.

To add insult to injury, on Sept. 2, the Swiss Football League (SFL) rejected the registration of one more player - Ghana's Brian Amofa. Then, on Sept. 30, the SFL decided to temporarily qualify the six new signings (whose illegal transfers into the club lead to its ejection from the 2011-12 Europa League), to comply with the ongoing legal process.

The players are - Swiss U-21 international Stefan Glarner, Frenchman Billy Ketkeophomphone, Belgium-born Luxembourg international Mario Mutsch, Guinean Pascal Feindouno, Portuguese Jose Goncalves and Spaniard Gabri.

In another twist to the saga, FC Sion then sued SFL and UEFA, in the Tribunal Cantonal de Valais and the Tribunal in Vaud, respectively. Both cases were later dismissed.

Meanwhile, UEFA has confirmed two possible courses of action should Basel fail to comply with FIFA regulations. On the one hand they could recall Manchester United. They could also give German club Bayern Munch, who have been drawn to play Basel in the last 16, a bye into the next round.

UEFA is confident that the Swiss FA will comply with the FIFA request before the deadline of January 13, 2012 and before the Champions League round-of-16 first leg match between Basel and Bayern Munich on February 22. Should this not be the case UEFA will review the situation nearer the time, Rob Faulkner, UEFA's Head of Communications, told Observer Sport on Saturday night, according to a Guardian report.