Spurs have seen three bids rejected for the Welsh striker with Forest holding out for a £50million transfer fee ahead of Friday night’s deadline.
Johnson, 22, is set to be in the starting line-up for Saturday’s trip to the capital if he stays at Forest, with Cooper providing an update on the situation in his pre-match press conference.
“If something’s going to happen then it’s coming to that time,” he said.
“We shall see. In terms of Brennan there’s no official news, we just have to carry on as normal. The boys are in for training and we’ll treat it as best we can like a normal day.”
He added: “I wouldn’t say there’s massive disruption to our planning [for the Chelsea game] apart from some injuries. We’ll just deal with it as it comes.”
Forest are hoping to complete a £2m deal to sign Arsenal left-back Nuno Tavares on loan as well as a £16m swoop for Corinthians defender Murillo. Cooper expects both deals to be completed.
“It’s busy at the moment,” he noted. “There’s some things that could happen, some things that might not and everything in between that.
“I do think there will be some players coming in, and I think there will be players leaving as well, with loans etc. There’s loads of moving parts. We would all like to add the right players to our squad. Any manager will tell you that.
“I do believe there are a couple of players - Tavares and Murillo - that are at the final stages. Not quite done, but the process is ticking along quite nicely. Hopefully I haven’t gone too soon on that, because until things are officially done then you never quite know. There’s a lot of work going on.”