With just hours of the transfer window to go for Spanish clubs and a move for Barcelona midfielder Rafinha looking difficult to conclude, Betis are thought to have turned their sights to the Argentina international.
According to the aforementioned source, negotiations between PSG and Betis have progressed at a rapid rate in the last few hours, with the Argentine potentially set to arrive in Andlausia imminently.
The deal would be an initial season-long loan, with Betis retaining the option to buy the player at an point duting the season for a set fee of €30m.
Betis had initially prioritised a move for Rafinha, but negotiations with Barca hit a roadblock, despite the Brazilian having agreed to the switch.
With Lo Celso looking unlikely to be handed too many first-team opportunities under Thomas Tuchel this season, he is thought to have jumped at the chance to head out on loan, with Betis also able to offer him European football.