Ralph Hasenhuettl, the Southampton manager, expects the defender Jannik Vestergaard to complete a move to fellow Premier League side Leicester City subject to a medical.
A reported £15m deal has been agreed for Vestergaard, who was in the final year of his contract with Southampton, having joined from Borussia Mönchengladbach in July 2018.
Vestergaard played in all six of Denmark's games at the European Championship in July as it reached the semifinals, where it lost 2-1 to England at Wembley.
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"He is doing the medical check, and when that is done, the deal is done," Hasenhuettl told a news conference on Thursday.
"He will go to Leicester, then it is for us to replace him, and this is what we will do in the future.
"We've made the squad bigger, with players with a future at this club. There is still one position to fill because we have lost Jannik."
Hasenhuettl has strengthened Southampton's forward line after last season's top scorer Danny Ings joined Aston Villa earlier this month, signing Adam Armstrong from Blackburn Rovers and Armando Broja on a season-long loan from Chelsea.
Southampton, which finished 15th last season, begins its 2021-22 Premier League campaign with a trip to Everton on Saturday.