Mignolet was an ample reserve in goal last season as Alisson made the No 1 shirt his at Anfield.
But the Belgian has now been plucked from Liverpool’s grasp by Brugge, who will fork out £6million for the shot-stopper.
That price could rise to £8m based on achievable bonuses – and Klopp plans to reinvest the money hastily.
The German boss did not want to see Mignolet leave and was impressed with his professionalism last season after losing his starting berth.
Klopp equally does not want to deprive the 31-year-old of first-team opportunities, however, and is, therefore, allowing the keeper to leave.
Mignolet could not turn down the chance to return to his homeland, where he has been away from since 2010 when he left Sint-Truiden for Sunderland.
The Belgian is understood to have travelled to Bruges following Liverpool’s loss to Manchester City in the Community Shield on Sunday.
The former Sunderland man is expected to complete his medical on Monday to finalise the move.
The transfer leaves Klopp in a pickle four days out from the summer transfer window deadline at 5pm on Thursday 8 August.
Youngsters Caoimhin Kelleher and Vitreszlav Jaros can offer short-term cover in the role, while veteran Andy Lonergan was drafted in for the club’s pre-season tour due to a shortage of available keepers.
But finding a keeper of Mignolet’s standard is Klopp’s priority and the manager would prefer to sign a proven professional to play second-fiddle to Alisson.
Cardiff man Neil Etheridge has been linked with The Reds this summer but no contact has been made as yet.
Former West Ham shot-stopper Adrian, who lost his first-team spot to Lukasz Fabianski last season, has been another touted name having recently become a free agent.
Klopp has made just two signings this summer in Dutch defender Sepp van den Berg and English youngster Harvey Elliott.
The 52-year-old is content with his squad, who won the Champions League last term, but these late developments in the window have sparked life into the Anfield front office.
The Merseyside club open the Premier League next Friday against newly-promoted Norwich at home.