Karius moved to Union Berlin last summer on a season-long loan deal to deputise for first choice Andreas Luthe at the Stadion An der Alten Forsterei.
The Reds star has struggled for game time at Union Berlin, only featuring five times so far this season across all competitions.
And according to German daily Abendzeitung Munchen, Union Berlin are not looking to keep shot-stopper Karius in their ranks beyond the current campaign.
Karius has struggled to impress with the limited game time he has had this season and is not part of coach Urs Fischer’s plans for the club’s future.
Union Berlin have already zeroed in on Eintracht Frankfurt custodian Frederik Ronnow as a replacement for Karius, who is due back at Liverpool at the end of the current campaign.
Karius is set to enter the final year of his contract at Anfield this summer, having been on the books at the club since the summer of 2016.
It remains to be seen how Liverpool will handle Karius’ situation in the summer with him also being deemed surplus to requirements by Jurgen Klopp at Anfield.