Borussia Dortmund winger Jadon Sancho has been unsettled by Manchester United's failed summer pursuit.
United unsuccessfully tried to sign the winger, 20, during the transfer window.
Tuesday's 3-1 defeat to Lazio in the Champions League has led to widespread criticism of the squad.
In particular, Sancho was panned by Bild for not being totally focused on the Borussia cause this season.
The German newspaper adds that there are rumblings inside the dressing room over the player's lack of discipline.
The Bundesliga side will need to turn things around quickly for Saturday's huge local derby against Schalke, with Zenit St Petersburg coming to Signal Iduna Park shortly after.