Swansea City have agreed an undisclosed fee for Barnsley defender Alfie Mawson.
The Welsh club have been on the lookout for a centre-back since captain Ashley Williams left for Everton this month.
Mawson, 22, joined Barnsley from Brentford in June 2015 and scored six goals in 48 league appearances as the Tykes won promotion to the Championship via the play-offs.
Swansea are yet to agree personal terms with Mawson and it is unclear whether Francesco Guidolin is still on the lookout for another defender with top-flight experience.
Mawson has already netted twice in four matches this season and will not be part of the Barnsley squad for Saturday's clash with Rotherham United, the Championship club confirmed.