Manchester City director of football Txiki Begiristain believes Schalke pose a threat if the Premier League champions allow the last-16 Champions League tie to be played on their opponents' terms.
Pep Guardiola's side were rewarded for winning their group with a trip to Gelsenkirchen in the first leg on February 20 – one of three Bundesliga-versus-Premier League ties after Liverpool and Tottenham were paired with Bayern Munich and Borussia Dortmund, respectively.
Second in Germany's top flight last season, Schalke have struggled domestically this time around having lost star midfielder Leon Goretzka to Bayern and are languishing in 13th.