Thompson was last week nominated by banned Essendon coach James Hird as the obvious choice to fill the role for the 12 months Hird has been suspended by the AFL.
Thompson, who coached Geelong to the 2007 and 2009 premierships but quit the Cats in 2010 saying he was burnt out, said he still found the idea difficult to contemplate.
"I'm still no clearer. I just don't know whether (I can). Right now the way I feel probably no," Thompson told Fox Footy's AFL 360 on Monday night.
Thompson acknowledged he was still in a "dark spot" emotionally as a result of the stress imposed by the anti-doping investigation the Bombers have endured.
He said he was not in a good state to be making decisions on his future.
"Probably not. I need to go away. I go away this weekend," he said.