Former Manchester City midfielder Dietmar Hamann has backed Leroy Sane to be a success at the Etihad, adding Raheem Sterling should be concerned by the club's latest arrival.
Sane completed his £37m move to City from Schalke on Tuesday, signing a five-year deal with the club.
The 20-year-old becomes Pep Guardiola's third high-profile signing of the summer, with Nolito and Ilkay Gundogan joining earlier in the transfer window.
Sane adds to City's attacking options with Sergio Aguero, Kevin De Bruyne, David Silva, Wilfried Bony, Jesus Navas, Samir Nasri, and Sterling vying for places in the starting line-up.
However Hamann, who enjoyed three seasons at City after joining from Liverpool, believes Sane's arrival poses the biggest threat to Sterling.
"If you look at the forward line they will probably play with one up top which will be Aguero. Behind you've got David Silva and Kevin De Bruyne who, when he is fit, will play," said Hamann.
"Then I think he'll probably come up against Raheem Sterling and, I've got to say, Raheem Sterling has pretty much stalled since he went to Manchester City.
"He's never showed the promise he showed at Liverpool earlier in his career, so I think Sterling will be the one who needs to pick it up.
"I think he will improve under Pep Guardiola - Leroy Sane said it himself - the biggest pull for him to come to Manchester City was to work with a manager who he knows will improve him."
Sane played 47 Bundesliga games for Schalke over the course of the last three seasons, but Hamann believes the 20-year-old has enough quality to replace the midfield goals lost by the decline in form of Yaya Toure.
"He's a very gifted player technically and he's got a lot of pace," said Hamann.
"He's not been prolific for Schalke over the last couple of seasons but I think he is a player who can and will score goals for Manchester City because that is one area - since the goals of Yaya Toure dried up - where they need improvement.
"They are very reliant on Aguero and De Bruyne when he came in a few months ago so I think he is a player that will give them that extra dimension going forward."
Sane could join up with the rest of the Manchester City squad in time for their pre-season friendly against Arsenal in Gothenburg on Sunday.
Pep Guardiola's side then host David Moyes' Sunderland in their opening game of the Premier League season at the Etihad on August 13.