The Chelsea midfielder spent the second-half of last season on-loan with Dortmund.
"We will definitely have some more discussions in the next few days about his situation," said Kehl, quoted by BBC Sport.
"I think it was a good move from Carney to join us. Now let's see how we manage everything. It won't be easy, but we will try to keep him because he's a very good player."
Chelsea are seeking £40m to sell Chukwuemeka this summer.
"It's always easier to loan a player than to buy one, especially within Carney's (price) range," added Kehl.
"But let's see. We are not that far advanced (in talks) at the moment, but I can tell you that we are pretty close to the player, and he loves Dortmund.
"Everything else will be decided between Chelsea and us. That won't be tomorrow. That won't be on Tuesday. I think it will take some more days."