According to the Daily Mirror, Southampton want to sign Tonny Vilhena as a possible replacement for Jack Cork, whilst the Daily Mail report that the Saints are interested in Vilhena's Feyenoord team mates Sven van Beek and Terence Kongolo.
The Saints have been superb so far this season, and with European qualification well within their grasp, manager Ronald Koeman will be looking to strengthen his squad on the South Coast.
Midfielder Cork has reportedly been given 48 hours to decide his future, with the ex-Chelsea youngster out of contract this summer - and Southampton have allegedly told him to make his mind up over a new contract or be sold before the transfer deadline later this month.
In his place could come Feyenoord's Tonny Vilhena, who of course worked under Koeman during their time together with the Dutch club.
The 20-year-old midfielder is considered to be one of the rising stars in Dutch football, and the left footed playmaker is reportedly seen as a potential replacement for Cork given Koeman's familiarity with him.
But the raid on his former club may not stop there, with the Daily Mail suggesting that summer bids for centre backs van Beek and Kongolo are on the cards.
Van Beek and Kongolo, both 20, worked with Koeman at De Kuip and will reportedly be scouted by Southampton on Sunday as they face rivals Ajax.
Van Beek is a big, strong centre half in the mould of a classic defender, whilst Kongolo is more athletically and technically gifted, whilst he also has the ability to play at left back too.
With Toby Alderweireld only on loan at St. Mary's Stadium, Koeman may need another centre back, and returning to sign players he's worked with before has already succeeded once with the purchase of striker Graziano Pelle last summer.