2015–16 season On 1 August 2015, he started his season by coming on as a substitute in the 84th minute. On 9 August 2015, Götze scored with a goal in Bayern's 3–1 DFB-Pokal win over FC Nöttingen. In the next four games, he struggled to make a significant impact in the squad. On 16 September, Götze, coming on as a substitute in 79th minute, scored the second goal against Olympiacos in the 2015–16 Champions League as his club earned a 3–0 away win. After the game, Bayern coach Pep Guardiola praised Götze for his performance. On 22 September 2015, Götze assisted the last goal in Bayern's 5–1 win against Wolfsburg. On 29 September, Götze was a threat whole game and he scored a goal against Croatian champions Dinamo Zagreb. Bayern earned a 5–0 win. On 4 October, Götze scored and assisted a goal against Borussia Dortmund to help Bayern to a 5–1 victory. He scored six goals in 21 appearances during the 2015–16 season. Return to Borussia Dortmund 2016–17 season On 21 July 2016, Götze confirmed his return to Dortmund on a four-year contract. He also stated that he regretted his decision to join Bayern Munich three years before. On 11 September 2016, Götze played his official comeback in 1–0 loss against RB Leipzig. Despite the loss, he was praised for his promising return. Three days later, he scored his first goal for Dortmund since his return to his boyhood club, with his previous goal in a competitive game for the club coming in the 6–1 Bundesliga win over Greuther Furth in April 2013. He scored the opener of the historic 6–0 away win against Legia Warszawa in the Champions League group stage. After a long time of re-adapting to the Dortmund system, Götze managed to find his form when their side faced Bayern Munich on 20 November 2016. Götze assisted the only goal of the game, and earned a 1–0 victory. Almost a month later, he scored his first Bundesliga goal since his return to Dortmund in a 2–2 draw against TSG 1899 Hoffenheim. In February 2017, Götze was dropped from the Dortmund team with a mystery illness, identified in media reports as myopathy, a metabolic disease which can cause fatigue and weight gain. The illness was said to explain some of Götze's fitness problems over the previous several seasons with Bayern and on his return to Dortmund. He