Messi did not show for Sunday's coronavirus tests and it seems clear he will not attend new coach Ronald Koeman's first training session as coach on Monday.
Both of those indiscretions would represent his first and second 'serious offences' and as both La Liga and the club believe that he is still under contract, this represents a breach of the collective agreement for players and clubs in the division.
If he were to refuse to attend a further training session, this could be treated as a third 'serious offence', one which could lead to a suspension of up to 30 days, or a fine of up to 25% of Messi's substantial salary.
Barcelona are being particularly careful in this case. They have not designated either incident as a 'serious offence' yet as they want to ensure that there is an opportunity for the situation to be resolved and for Messi to still have a future at Camp Nou.
Messi meanwhile believes that he has already informed the club, via burofax, that he is no longer a Barcelona player and therefore he is not obliged to attend any events.
President Josep Maria Bartomeu and Messi's father, Jorge, are expected to meet towards the end of the week to continue discussions in an attempt to resolve the issue.