An economics professor at the University of Barcelona says that, even if Argentine soccer superstar Lionel Messi's tax evasion case goes to trial and he is convicted, he can still avoid prison by regularizing his tax situation.

In an interview with RAC-1 radio, Josep Maria Gay de Liebana said he was surprised the 25-year-old FC Barcelona striker, a four-time world soccer player of the year, was hit with the complaint - filed by the prosecutor's office for tax crimes of the Spanish autonomous community of Catalonia.

He said the player was in this legal predicament because his tax consultants had not adapted their strategy to Spain's rapidly changing tax code.

Messi is accused of defrauding the Spanish state of some 4.1 million euros ($5.5 million) in unpaid taxes related to income from publicity contracts that he allegedly failed to report on his 2007, 2008 and 2009 tax returns.

According to prosecutors, Messi simulated the ceding of his image rights "to shell corporations in tax havens (Belize, Uruguay) and, in complementary fashion, formalized licensing, agency or service-provision contracts between those corporations and other shell companies domiciled in convenient jurisdictions (Britain, Switzerland)."

They said the purported fraud scheme was orchestrated by the star player's father and agent, Jorge Horacio Messi, adding that in 2005 - when his son was still a minor - he entrusted a third party to create an initial shell corporation for tax-evasion purposes.

The purpose of the alleged scheme, according to prosecutors, was to transfer revenues from countries where large sums were paid for use of the player's image to shell corporations domiciled in tax havens.

The idea was for the income "not to be submitted to any taxation, with total lack of transparency toward the Spanish Treasury by the real recipient and beneficiary of this income, who was none other than the defendant, Lionel Messi."

Gay de Liebana said the player still might avoid trial, "although usually when it gets to this situation it's because all avenues of dialogue have been exhausted." The decision on whether to bring the case to trial is up to a judge in the Barcelona suburb of Gava, where the suit was filed.

The professor added that it was possible the soccer star could end up in prison, although he deemed that unlikely because he could "settle and regularize his situation" before that happened.

The academic, an expert on tax issues affecting athletes, said Messi was not the first FC Barcelona player to come under scrutiny, adding that top-level sports stars "are very atypical taxpayers; they are money-making machines."

He noted that, as a resident of Gava, Messi must pay Spanish taxes on all of his income at the top rate of 56 percent.

Messi, for his part, released a statement Wednesday denying the accusations, saying he had learned about them through the media and was surprised at the news.

"We have not committed any infringement. We have always fulfilled all of our tax obligations, following the advice of our tax consultants, who will take care of clarifying this situation," the player said on his Facebook page.

Tax fraud is punishable in Spain by up to six years in prison.