Bielsa was officially expected to take over on July 9 according to his contract and he and his staff were expected to arrive in Rome on Saturday. Instead Lazio and President Claudio Lotito will begin legal proceedings against the Argentine
“We have received the surprise resignation of Mr Marcelo Bielsa,” read a club statement.
“On behalf of his employer, he is in clear violation of the commitments undertaken with the contracts signed last week, which were then deposited to the league and the football federation.
“The club [Lazio] reserves all actions to protect its rights. The team will now be entrusted to Simone Inzaghi.”
Prior to taking up the Lazio job, Bielsa was strongly linked with a second stint with Argentina, with his departure from the Stadio Olimpico club coming just three days after Gerardo Martino’s resignation.
Bielsa, who quit French side Olympique de Marseille after the first match of last season, had a six-year spell as Argentina boss between 1998-2004, guiding them to gold in the 2004 Olympics in Athens and to the final of the 2004 Copa America.
Lazio have not won the Italian title since 2000 and finished eighth last season.