Nicklas Bendtner says his situation at Wolfsburg is "unsustainable" amid reports he is seeking a return to England.
Former Arsenal striker Bendtner, 27, resumed training with Wolfsburg earlier this week but could leave the Bundesliga club before the close of the transfer window.
Since signing a three-year contract with Wolfsburg in 2014, the Denmark international has struggled to establish himself in the first team and he told Bild: "My situation is clear. I am unhappy.
"Everyone can add up the numbers. We played a total of 53 matches in 2015, and I started five of them."
He also told BT he would respect his contract but added: "My situation is undoubtedly unsustainable."
Bendtner scored eight goals in 28 league games during a loan spell at Sunderland in 2011-12 and local paper Wolfsburger Allgemeine Zeitung has reported that he could now seek a similar move in an effort to secure regular playing time.
Meanwhile, Bild has reported that fellow Wolfsburg striker Bas Dost is also considering leaving the Volkswagen Arena after dropping down the pecking order.
Dost, who has scored nine goals in 23 games in all competitions this season, did not start the club's final four matches of 2015, with coach Dieter Hecking preferring Germany international Max Kruse in attack.
The Netherlands international has been linked with Premier League strugglers Newcastle United in the past.