Sheffield Wednesday will bolster their defence before the transfer window closes this week.
Reports in Holland claim that the Owls hierarchy are in talks with Heerenveen with a view towards signing Joost van Aken.
The 23 year-old is said to have been courted by Lazio, however Dutch news outlet De Telegraaf states that the centre half is close to moving to Sheffield. Van Aken sat out his side’s 2-1 win over Den Haag on Sunday.
Wednesday have been struggling for options at the back already throughout this season with only two recognised senior centre-halves at the club when the campaign began.
That was made worse by an injury to Glenn Loovens, with regular left-back Daniel Pudil having to cover in the middle alongside Tom Lees.
Portuguese defender Frederico Venancio was signed from Vitoria de Setubal but he has only just received international clearance and has yet to feature.
Carvalhal admitted: “We are trying to find another centre-back. We need four.”
“We try to see what we can do to upgrade the team,” added the head coach. “It is a long season and we need more options. I believe something will happen in the next days. We must wait and see if we can achieve the players that we want.”
A new central midfielder also features on Carvalhal’s wish-list.
Van Aken was an almost ever-present in the Heerenveen side last season until having to undergo ankle surgery towards the end of the campaign, in which he missed the final seven games including the two-legged Europa League play-off with Utrecht. Heerenveen lost all but one of those matches.