The Senegalese international endured a tough time at old Trafford, failing to live up to the potential that tempted Sir Alex Ferguson secure his signature in 2009.
He joined Blackburn Rovers on loan before moving to Bundesliga outfit Hannover last January.
Since signing for the German side, Diouf has rediscovered the form that once made him one of the hottest properties in European football.
This has reportedly tempted Villa boss Paul Lambert, who is keen to bolster his attacking options this winter.
Former club captain Darren Bent looks likely to leave Villa Park after falling out of favour with his manager and if he does indeed leave the Midlanders will be short on attacking options.
Gabriel Agbonlahor and Christian Benteke are able to occupy the role, but it is thought that Lambert would prefer to have another option.
Diouf started his career with home nation club Diaraf, before switching to Norwegian giants Molde, where his impressive scoring record attracted the attention of Manchester United.