Swansea have agreed an undisclosed fee with Barnsley for their central defender Alfie Mawson.
Hillingdon-born Mawson joined Barnsley from Brentford in June 2015 after the player had loan spells at Luton, Welling and Wycombe.
Mawson has made 64 appearances and last season was a part of the Barnsley side which won the Sky Bet League One play-offs and lifted the Football League trophy at Wembley.
"The move is subject to the 22-year-old agreeing personal terms at the Liberty," said a statement on the official Swansea website.
Swansea manager Francesco Guidolin had targeted a central defender following the departure of club captain Ashley Williams to Everton.