Fulham are determined to bolster their defensive options before the close of the transfer window, and are hoping to lure Mancienne to Craven Cottage.
Mancienne came through the youth ranks with Chelsea but only played six first-team games for the Blues.
The former England Under-21 international enjoyed loan spells at Wolverhampton Wanderers and two at Queens Park Rangers before leaving Chelsea permanently in 2011 for German club Hamburg.
After three years in Germany, Mancienne returned to England to join Nottingham Forest and he made 38 appearances in all competitions last season in his debut campaign at the City Ground.
Mancienne has started all five of Forest's games this season and has established himself as a key member of Dougie Freedman's side.
Forest are reluctant to lose Mancienne, but Fulham have tested their resolve with a firm bid for the 27-year-old.
Fulham boss Kit Symons sees Mancienne as someone who will prove a valuable addition to his squad as he can play in defence and in midfield, offering options to his side.