The 20-year-old rose to prominence after starring on loan at Premier League side Everton last term.
Deulofeu made 29 appearances for Roberto Martinez's men in all competitions, scoring four goals.
He was expected to be a part of Barca's first-team squad in the 2014-15 campaign, but has featured only sparingly during pre-season.
And new Barca coach Luis Enrique has now decided that Deulofeu's progression will be best aided at Ramon Sanchez Pizjuan Stadium under the stewardship of Unai Emery.
"Barcelona and Sevilla FC have reached an agreement in principal for the transfer of Gerard Deulofeu for the 2014-15 season," read a statement on Barca's official website.
"[The move] is designed to ensure that he gets to play as many games as possible and therefore develop as a footballer."
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