The Argentine head coach was originally believed to have signed a two-year deal at the Stade Velodrome, though it was later confirmed he only had a 12-month agreement in place after taking over in May last year.
An impressive campaign has seen Bielsa return Marseille to the Ligue 1 title fight with Lyon and Paris Saint-Germain, reportedly attracting the attention of Japan and Saudi Arabia's national sides.
"Such rumours are common during this time of the year," Bielsa said.
"There is nothing new to say. I only speak of concrete facts and I will not confirm or deny this.
"All I can say is that both sides have agreed to this.
"As soon as the season ends, the contract ends. Will I stay at OM? I can't eliminate the possibility. But I can't confirm it either."
Bielsa takes his side to Saint-Etienne this weekend looking to get back to winning ways after two draws, results he blames himself for.
"In the last game [2-2 against Reims] I took too long to make my changes," added the head coach. "The team was unbalanced in defence.
"[But] I do not like to make changes to the game situations. The big teams adapt."
