Colchester have signed former Yeovil midfielder Joe Edwards, subject to paperwork.
Southampton have announced the signing of versatile defender Cuco Martina from FC Twente on a two-year-deal.
Former Manchester United forward Diouf is tied to Hannover until the summer of 2014.
He is, however, said to be a target for Borussia Dortmund, with nine goals in 17 appearances this season bringing him to the attention of the Bundesliga's top sides.
Hannover, though, are reluctant to discuss a sale and claim they are planning to offer fresh terms to the Senegalese frontman.
Manager Mirko Slomka told ZDF Media: "Mame Biram Diouf is an exceptional striker.
"We are happy to have him at our club and we will do our best to ensure that he remains with us.
"It is normal that other clubs are interested in a player like this. That does not mean that he automatically has to move clubs.
"My wish is to see a contract extension with Diouf put in place."