Former Borussia Dortmund star Karl-Heinz Riedle has little doubt Mario Gotze will return to his best at Signal Iduna Park after an underwhelming spell with Bayern Munich.

The Germany international left Dortmund for Bayern in 2013, but failed to live up to the high expectations at the Allianz Arena and signed a four-year deal with BVB on Thursday to complete his return to his boyhood club.

Some have questioned Dortmund's decision to re-sign the attacking midfielder, but Riedle is confident the 24-year-old will make an immediate impact.

"Gotze is a brilliant player," Riedle told Bild.

"It is important for him to have returned to the BVB family and to be back home. He will not have forgotten how to play football.

"I don't think he was as bad as some made him out to be at Euro 2016 in France.

"It's not like he is a player who has hit rock bottom. Thomas Tuchel will just have to get a few things right. We have all seen last year with Henrikh Mkhitaryan what he can do with a player."