New Bluebirds' boss Ole Gunnar Solskjaer worked with the former Manchester United player at Molde, and is keen to secure his services once again.
Norway international Magnus Wolff Eriksson has already joined Cardiff, while a deal for his compatriot Mats Moller Daehli is expected to be completed before the weekend meeting with West Ham.
And Solskjaer is now also looking to bring in Diouf after a Hannover spokesperson confirmed to Press Association Sport the Bundesliga club had received an approach from Cardiff.
Cardiff are believed to be prepared to pay around £2.5million to sign the 23-year-old, who has scored 30 goals in 61 appearances for Hannover.
- Sports & Recreation
- Ole Gunnar Solskjaer