Chris Martin is currently in Dubai mulling over his decision whether to join Sunderland on loan or not this month, Sky Sports News understands.
The 29-year-old striker is there with the rest of the Derby squad for some warm-weather training.
Derby boss Gary Rowett admitted at the weekend that Sunderland were in for Martin along with some other clubs.
Sky sources understand another to be Reading.
Sunderland boss Chris Coleman also confirmed they are waiting on Martin's decision, which is not likely to come until the Rams return to the UK later this week.
Coleman said: "We thought that something was over the line but at the minute it is not. We have got a deal with a club and we are waiting for an answer and a decision from a player."
Rowett said: "We have some strong interest in him, and Sunderland are one of those teams, but until the player decides he wants to go somewhere and signs on the dotted line, whether that is a loan or a permanent deal, then he is our player."