Elian Parrino is back at Bramall Lane after the Blades strengthened ties with top Argentine club, Estudiantes de la Plata.
The versatile defender, 22, has signed a year's deal and returns after impressing when playing nine times during a loan spell with United last season.
He told sufc.co.uk: "I'm really happy to be back, I want to play in England because I enjoyed it here last season - the stadiums, facilities and fans are fantastic. It was about three weeks ago when I heard that there was a chance to come back and I made it known that's what I wanted.
"I didn't play so much last year but my time with United certainly helped me become a better player and hopefully the fans will get to see that. I'm better now physically, mentally and technically."
The relationship between Estudiantes and United has a number of interesting facets. It began with former Blade Alex Sabella, who recently was appointed as manager of the Argentine national team, at the helm of Estudiantes which helped instigate relations.
Estudiantes captain Juan Sebastian Veron's uncle, Pedro Verde, also played for the Blades and Veron himself is said to have dreamed of playing for the Blades as a young boy.
Estudiantes legend Juan Ramon Veron, father of Juan Sebastian, an ambassador for the Argentines commented: "We are very keen to continue this relationship with Sheffield United and pleased to see Elian return to England.
"We will be watching and supporting Elian from Argentina. We here at Estudiantes would like to thank all the people involved and hope this will lead to opportunity for more of our young talented players and benefit for both clubs."