The 26-year-old playmaker has been at the Mestalla since 2008 but spent last term on loan at Newell's Old Boys in his homeland, featuring 20 times in all competitions and scoring once.
Banega, who also spent a season on loan at Atletico Madrid during his time with Valencia, will move to Sevilla provided he passes a medical and agrees personal terms.
"Ever Banega can become a new player of Sevilla FC if he passes the medical tests in the next few hours and the documents are signed," read a statement on Sevilla's website.
"Sevilla FC and Valencia reached an agreement in principle for the transfer of the Argentinian midfielder on Sunday afternoon."
Sevilla, last season's UEFA Europa League winners, have been active in the transfer market during the close-season, with Banega set to become the eighth arrival as Unai Emery looks to cope with the losses of Ivan Rakitic and Alberto Moreno, who have joined Barcelona and Liverpool respectively.
Emery has brought in the likes of Barca duo Gerard Deulofeu and Denis Suarez on loan, as well as Grzegorz Krychowiak from Reims.
