Callum Styles has joined Championship club Millwall on loan for the remainder of the season and signed a new Barnsley contract until 2025.
There is no option for the Lions to buy Styles, as part of the deal, the Chronicle understands.
He joins Michal Helik, Callum Brittain, Carlton Morris and Cauley Woodrow in leaving the club this summer.
Barnsley had a busy final evening of the transfer window, signing Burnley midfielder Adam Phillips on a three-year deal and loaning in Tom Edwards from Stoke. Michael Helik was sold to Huddersfield, and Clarke Oduor loaned to Hartlepool United.
Styles signed in 2018 then, after a loan back to his previous club Bury, was a fringe player in the side that got promoted in 2019.
He burst into the first team during behind-closed-doors football in the summer of 2020 as a left wing-back, having initially been a central midfielder.
He continued to excel on the left under Valérien Ismaël in the 2020/21 season, in which Barnsley reached the play-offs.
His form dipped last season, like most players, as he was used in various positions including attacking midfield for the Reds who finished bottom of the Championship.
But Styles still received international recognition, being called up for Hungary who he qualifies for through his grandmother. He made his debut in March then played in the 4-0 win over England earlier this summer.
He has been expected to leave Barnsley all summer but has started each of their six games so far, scoring in the 2-2 draw at Ipswich Town on Saturday.