Brentford defender Mads Bech Sorensen is expected to be sidelined for three months with knee ligament damage.
Sorensen limped off during the Bees’ Carabao Cup win against Forest Green Rovers last month.
It has not yet been established whether the 22-year-old Dane will undergo surgery.
Boss Thomas Frank said: “It’s a longer-term injury unfortunately. He’ll be out for around three months.”
Sorensen’s injury prompted Brentford to bring in Denmark international centre-back Mathias Jørgensen.
The 31-year-old has agreed a one-year contract with the option of a further year.
He can be signed outside of the transfer window because he was a free agent, having left Turkish club Fenerbahce this summer.
Jørgensen has played in the Premier League before, having been at Huddersfield Town between 2017 and 2019.
His career has also included spells with PSV Eindhoven, FC Copenhagen and German club Fortuna Düsseldorf.
“We are pleased that we could strengthen our squad and bring in a top quality experienced player to the group. This was especially important after Mads Bech picked up an injury,” Frank told the club website.
“Zanka brings a wealth of experience from different leagues and a lot of international games, he has also played in the Premier League before.
“That experience and leadership is especially important, and it is great to get him in.”