The London club have already rejected an offer of £9million plus Spanish striker Kike joining on loan from Boro.
The report claims that Boro are prepared to make an improved offer of £12million for the Scotland international who is hoping to seal a move to the Riverside Stadium before the winter transfer window slams shut.
McCormack has not trained with the Cottagers for the past week and was present in the stands during the 1-0 defeat to Hull City on the weekend.
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