The 32-year-old has allegedly reached an understanding with his club that he can leave if a suitable offer arrives. According to Sky, the agreed transfer fee would be in the region of €400,000 to €500,000.
Mickels remains under contract with Sabah until 2028, but is said to have attracted enquiries from several clubs ahead of the winter window.
The forward is currently preparing to face Borussia Dortmund in the Champions League, giving him an immediate connection to the German top flight he wants to join. He has made clear that returning to Germany would appeal to him, particularly if it meant rejoining the club where his football journey began.
“Who doesn't want to play in the Bundesliga? I think it is one of the most attractive leagues in the world,” Mickels said.
The Rwanda international has a particular affection for Borussia Monchengladbach, where he spent time during his youth career. He would welcome the chance to return to the club, although there is no confirmation that Gladbach are among the teams interested in signing him.
“Of course, Borussia would be the ultimate. I wouldn't turn down an offer from Borussia — once a Borusse, always a Borusse,” he said.
Mickels was born in Germany and has represented Rwanda at international level, earning four senior caps. He can play as a central striker or operate in wider attacking positions.
His record for Sabah has been productive. The forward has registered 82 goals and 34 assists across 156 appearances for the club, giving him 116 direct goal contributions.
That output could make him an attractive option for a German club looking for an experienced attacker at a relatively modest transfer cost. However, any move would depend on a suitable offer and agreement between the clubs.
With his contract running for another two years beyond the current season, Sabah are not obliged to sell. The reported understanding over a fee would nevertheless give Mickels a possible route out if a Bundesliga opportunity materialises.
For now, his immediate focus is on Sabah's European campaign, with the Dortmund fixture providing a high-profile stage as speculation grows about his next move.