Blatter and Platini will have disciplinary hearings before FIFA ethics judge Hans-Joachim Eckert in Zurich on Thursday and Friday, over a £1.3million ($2.72 million) payment made to Platini by FIFA in 2011 and signed off by Blatter.
Outgoing FIFA president Blatter and UEFA president Platini face charges including corruption, conflict of interest and non-cooperation. Sources with knowledge of the case say that it will be difficult to prove corruption, which carries a lifetime ban, but believe there is clear evidence of a conflict of interest in the payment being made.
That should carry a ban of at least seven years, but it is likely any suspension for wrongdoing will effectively end their careers in football politics.
Blatter's case will be heard on Thursday with Platini's following on Friday. A decision is expected to be announced by Monday next week.
The 2million Swiss franc payment was made to Platini in February 2011. The Frenchman and Blatter say the payment was honouring an agreement made in 1998 for work carried out between 1998 and 2002 when Platini worked as a technical advisor for the FIFA president.
However the payment was not part of Platini's written contract - they have insisted that it was an oral agreement which is legal under Swiss law.
The timing of the payment has raised eyebrows however - it took place nine years after Platini had stopped working for FIFA, and was made while Blatter was seeking support for a fourth term as president. Several weeks after the payment was made Platini and UEFA's executive committee endorsed his candidacy.
Both Platini and Blatter have denied any wrongdoing - Platini has said he had not been paid the full amount agreed in 1998 because of FIFA's financial situation at the time.
South Korea's former FIFA vice-president Chung Mong-Joon was banned for six years in October for conflict of interest and non-cooperation - the latter offence can simply be having publicly criticised the FIFA ethics committee. Chung's case would appear however to be less serious than that facing Blatter and Platini.
Blatter and Platini are likely to challenge any ban and take the case all the way to the Court of Arbitration for Sport.
Meanwhile, FIFA has appointed Harvard professor John Ruggie to provide recommendations on a new human rights policy that will cover future World Cup hosts.
The appointment follows several reports criticising worker rights in 2022 hosts Qatar and Ruggie will make his proposals in March.
