Messi made a shock move to Paris Saint-Germain after Barca revealed they could not afford to offer him a new deal at Camp Nou. The Argentine, along with the rest of the squad, deferred salaries last year due to the financial impact of the coronavirus, and are owed a combined £104m.
Messi trained with his new teammates for the first time on Thursday and could be included in Mauricio Pochettino's squad for Sunday's visit of Strasbourg.
Earlier this week, Barcelona and Real Madrid rejected LaLiga's £2.3bn investment deal with private equity firm, CVC, and are considering taking legal action against the pair.
CVC Capital Partners purchased a 10 percent stake in LaLiga earlier this month, but the proposal has been turned down by the league's giants. Madrid have claimed that they were not informed of the deal and that some terms are against the law. A statement published on the club's website read: "This agreement was reached without the involvement or knowledge of Real Madrid and today, for the first time, La Liga has given us limited access to the terms of the agreement.
"The clubs have signed over their audiovisual rights exclusively for their sale on a competitive basis for a period of three years. This agreement, by way of a misleading structure, expropriates 10.95% of the clubs' audiovisual rights for the next 50 years, in breach of the law."
Barcelona said in a statement: "FC Barcelona considers that the operation that has been made public has not been sufficiently verified with the clubs [owners of the TV rights]; that its amount is not congruent with the years of duration and that part of the audiovisual rights of all the clubs are affected for the next 50 years.
"FC Barcelona wants to show its surprise at an agreement promoted by Laliga in which it has not had the criteria of teams, like FC Barcelona itself, and does not even show options among more competitors to be able to evaluate the advantages and disadvantages in a scenario with many questions such as the post-pandemic."