By Aleks Klosok and John Sinnott, CNN

(CNN) -- Barcelona forward Lionel Messi did not attend pre-season training on Monday, a club source has confirmed to CNN Sport.

The source spoke on the condition of anonymity, in keeping with the club's rules about official statements to the media.

The news comes after the 33-year-old failed to show up for a coronavirus test at Barcelona's training ground on Sunday, casting further doubt on his future at the La Liga powerhouse.

Under La Liga rules, without passing a test, Messi will be unable to take part in pre-season training under new coach Ronald Koeman, with the 2020-21 season in Spain set to start in two weeks.

The source also denied multiple reports in Spanish and British media that Messi's father and agent, Jorge Messi, would be meeting with the club's board this week to discuss his son's future.

According to multiple reports, Messi believes he has a clause in his contract which allows him to leave Barcelona for free this summer.

Reportedly, the clause expired on Wednesday 10 June, but Messi and his representatives believe he still has the right to activate it now due to the season being extended because of the pandemic.

However, Barcelona insist that he must see out his contract, unless a release clause is paid, believed to be 700 million euros ($833 million).

"The club is not willing to enter into any negotiation for the player's departure. The position of the club is that Messi has a valid contract until 30 June 2021 which the club would like to extend," added the source.