The Portuguese youngster joined in a surprise £7.4m deal from Vitoria de Guimaraes earlier this month.
But, according to the Guardian, below par training performances led reserves boss Ole Gunnar Solskajer to leave him out of the second string squad to face City, when boss Sir Alex Ferguson was supposed to be casting an eye over him.
Ferguson admitted the Bebe deal was the first time he had ever bought a player without watching him, but he came with a recommendation from former United assistant Carlos Queiroz after making a rapid rise up the Portuguese leagues.
Source: Manchester Evening News