Hertha Berlin sporting executive Michael Preetz has said the club hope to keep Liverpool midfielder Allan for another season, although his parent side are keen for the player to be competing in the Europa League.
Having joined Liverpool from Porto Alegre in 2015, Allan has to yet appear for the Premier League club.
He spent time with SJK in Finland and Sint-Truiden in Belgium before joining Bundesliga club Hertha for the current campaign.
But with Hertha's failure to reach Europa League through the qualifiers last summer, and Allan's participation in the South American Under-20 Championship in early 2017, the midfielder played in only 15 matches in all competitions and failed to meet the requirements for a work permit in England.