CNN  — 

Pep Guardiola is once again splashing the cash as he attempts to plug the holes in Manchester City’s leaky back line.

Portuguese club Benfica said on its website that a €68 million ($79.2 million) fee had been agreed with City for the transfer of central defender Ruben Dias, with the possibility of an additional €3.6 million ($4.2 million) in performance-based add-ons.

“This agreement is dependent on the signing of the player’s sports labor contract with Manchester City,” said Benfica on its website.

The Portuguese club’s statement also said that Nicolás Otamendi will move from City to Benfica for €15 millions ($17.5 million). City has yet to comment on either transfer.

Sunday’s 5-2 hammering at the hands of Leicester in the Premier League provided plenty of evidence to Guardiola of his team’s defensive weaknesses. Dias’ arrival will bring the Spaniard’s total spending on defenders alone in his four years at City to $500 million.

Last month, City signed central defender Nathan Ake from Bournemouth in a reported $50 million deal.

Among the multitude of expensive defenders purchased by Guardiola, arguably the only success story has been Aymeric Laporte, though the Frenchman’s impressive time with City has been blighted by persistent injuries.

READ: Jaime Vardy hits hat trick, Leicester City scores five as it thrashes Manchester City

Pep Guardiola will hope Ruben Dias is the answer to his defensive headache.

However the jury remains out on a swathe of defensive players that have joined City for significant transfer fees during Guardiola’s time at the club.

Joao Cancelo was signed from Juventus for $71 million – with Danilo, another defensive disappointment at $33 million, going the other way – Benjamin Mendy for $63 million from Monaco and John Stones for $60 million from Everton.

The 32-year-old Otamendi also endured an inconsistent five-year spell at City after signing for a reported $41.2 million from Valencia.

City’s defensive frailties since failing to replace talismanic center back and captain Vincent Kompany saw the club fall well behind rival Liverpool, which romped to the Premier League title last season.

Pep Guardiola's City was hammered 5-2 by Leicester on Sunday.

The 23-year-old Dias, who Guardiola will hope is the missing piece to the team’s defensive puzzle, came through Benfica’s vaunted youth system and has been a mainstay in defense for the past three years.

Dias, who captained the side and scored in Saturday’s 2-0 league win over Moreinense, was also selected to be part of Portugal’s 2018 World Cup squad.