Former Bayer Leverkusen defender Manuel Friedrich could replace the injured Neven Subotic at Borussia Dortmund for the remainder of the season, pending a successful trial.
Serbia international Subotic suffered a posterior cruciate ligament and medial collateral ligament injury in his right knee during Saturday's 2-1 defeat at Wolfsburg. While the centre-back says he "will come back even stronger", a minimum six-month spell on the sidelines has all but ended his season.
With Germany international Mats Hummels and Greece international Sokratis only two experienced centre-backs remain in Juergen Klopp’s side.
On Tuesday, former Leverkusen defender Manuel Friedrich, 34, joined the Dortmund squad for a trial. The former Germany international has been out of contract since the summer break, when new Leverkusen coach Sami Hyypia did not renew Friedrich’s deal.
Over the past few weeks Friedrich has trained with fourth-tier team RW Oberhausen while awaiting offers from Asia, where he envisioned ending his career.
"We not only lost a game at Wolfsburg but most of all Neven Subotic," Klopp told Dortmund's website. "The extent of the injury forced us to rapidly consider how to cope with that. We still have eight games in three competitions until the winter break."
With the transfer window currently closed and defensive prospects Koray Guenther and Marian Sarr struggling to impress with the club’s reserves, Klopp has called on Friedrich, his former charge during his tenure at Mainz.
"Until now he has mostly kept fit at RW Oberhausen," Klopp said. "And we are now looking at his fitness and if that suits us. From a personal perspective, I’ve experienced that a couple of years ago, it fits.
"He brings in a lot of experience, he has class. Now we need to see how he is holding up from a sporting perspective. At the end, we’ll see how it goes on in order to make the right decision in shortness of time."
Friedrich has played a total of 247 Bundesliga games and 80 Bundesliga II games. He has won nine caps for Germany but, during the 2012-13 season, played only 11 league games for Leverkusen, starting a mere five of them.
While Friedrich would be eligible to play in Bundesliga and the German Cup, he could not be called up into the Champions League squad for the crucial group matches against Napoli and Marseille.