Acuna will replace Sergio Reguilon at the Ramon Sanchez Pizjuan should the deal go through.
Reguilon has returned to his parent club Real Madrid and is attracting interest from around Europe after an excellent season in Seville.
Acuna is training separately from his Sporting teammates, a sign that a transfer is imminent.
Aware that Sporting need some cash to invest in players, Sevilla did not meet their initial demands for Acuna.
Sporting wanted €20m then dropped the price to €15m, but Sevilla believe they can get Acuna for around €10m.
The Lisbon club would hope for more than that as it is similar to what they paid for Acuna in 2017.
Acuna has been one of Sporting’s best players in recent years, leading to him becoming a regular for Argentina.