Saints are expected to make Florin Gardos their sixth signing of the summer within the next 24 hours – but Sam Byram looks unlikely to be the seventh new face at St Mary’s.
Gardos will arrive from Steaua Bucharest for a fee of about £6m, as a replacement for Dejan Lovren.
He will almost certainly not be joined by Leeds defender Byram, however.
The 20-year-old right-back had been identified last month as an option to provide cover for Nathaniel Clyne, following Calum Chambers’ £16m move to Arsenal.
However, despite being willing to pay £4.5m for the player, Saints’ attempted advances were ignored by the Championship club.
It is believed that they have since decided to not to pursue the matter and will instead provide cover for Clyne from within the squad.
The club are not blessed with natural options in that position, beyond their number-one choice, but Jack Cork has experience of playing the position and represents a solid alternative.
The back line is set to receive a significant boost as early as today, though, with Gardos due to finalise his move.
His capture is seen as one of the last key signings ahead of the new season.
The 25-year-old Romanian international arrives as a replacement for Lovren, who was sold to Liverpool for £20m this summer.
Assuming his move goes through as anticipated, Gardos is set to line-up on the opposite side to his predecessor on Sunday, when Saints visit Anfield.
He will become the partner for Jose Fonte in the heart of defence, with the newly-appointed team captain having operated alongside either Yoshida or Jos Hooiveld in pre-season.
The arrival of Gardos effectively signals the end of Saints’ interest in Sporting Lisbon defender Marcos Rojo, with the Argentine international now reportedly the subject of a bid from Manchester United.
As well as another striker, with Hull's Shane Long a target, Saints are also considering adding an additional wide player if they can find a suitable option.