Borussia Dortmund head coach Thomas Tuchel is confident Mario Gotze will return to be an important part of his squad after being ruled out for an unknown period.

Gotze, who has missed Dortmund's last six matches, has been sidelined indefinitely by "metabolic disorders" that are said to be behind his recent injury problems.

Tuchel reiterated the need for Gotze to take some time away from first-team action but expressed optimism that he would one day be a key figure again.

"We need peace, calm and tranquillity for Mario," he told a news conference.

"He needs rest, understanding and support - all of which he will get here.

"It takes time for the best treatment. Then he will be an important part of the team again."

Dortmund's DFB-Pokal quarter-final away to third-tier side Sportfreunde Lotte was snowed off in midweek, and Tuchel hopes the postponement will prove to be a blessing in disguise ahead of Saturday's Bundesliga clash with Bayer Leverkusen.

"We had more training time and more time to regenerate," he added. 

"My team is doing excellently well at the moment, their energy and quality is outstanding, their desire for training as well.

"They ensure a high level and we feel very fit for the tasks that are on the agenda."