Nuri Sahin said he was delighted to be back at Borussia Dortmund as he looked ahead to what could be his first appearance at the Westfalenstadion since April 2011.
Sahin, 24, returned to the club after spending 12 months at Real Madrid and a further six on loan at Liverpool, and came on as a substitute in the 5-0 win at Werder Bremen last weekend.
The Turkey international has signed an 18-month loan deal, which reportedly also includes a €7 million option for Dortmund to make the transfer permanent.
Sahin, who could be involved in the game against Nurnberg on Friday, told Ruhr Nachrichten: "I can only go 100% when I am happy. This wasn't the case at Madrid and Liverpool. That's why I wanted to return to Dortmund."
He said he believed his move to Spain had suffered because he had carried a knee injury into his first pre-season at Real.
"I thought about this a lot," he explained. "It cost a lot of energy. I knew things would have been different if I hadn't been injured. But that was my fate.
"It might have looked like I failed. I would not see it like this. During my time at Madrid, I suffered injuries to my intra-articular ligament three times over a short period of time."
During Sahin's absence, Dortmund won the domestic double and Ilkay Gundogan filled the gap in midfield.
"I know the game has changed," Sahin said. "I must bring in my qualities and become an even better player than I was to help the team.
"I just hope this story here will last for a long, long time. I know where I want to be. And I am there now."