Sidwell has struggled to hold down a first-team spot at Villa, and the Hammers are keen to link him up with Scott Parker in their midfielder.
West Ham coach Wally Downes worked with Sidwell at Reading, and that relationship could help the move go through.
Sidwell's contract ends next summer and Villa are said to be happy with him talking to other clubs in January.
- - -
Talksport are also the messengers for a story linking Giovani Dos Santos to Genoa.
The Tottenham midfielder has been largely unimpressive since joining from Barcelona in 2008, and talks are reportedly at an advanced stage with the Serie A side.
Once Harry Redknapp gives the move his approval, Dos Santos can leave.