The Daily Mail says Keegan's return has failed to galvanise a set of players short on numbers, quality and confidence and he will make another effort to persuade Shearer that he can find the time in his schedule to do more than just take the occasional coaching session.
Keegan, however, desperately needs to find a spark to ignite a club in major trouble and wants Shearer on board.
"I've definitely not given up on it," he said. "What we have agreed is that he is going to come in training with us to start off with and then we are going to revisit it later when the commitments that he's made to other people are no longer in place.
"The door is left absolutely wide open. It's up to Alan and me to come up with the right solution for him coming in here. I've left the door wide open because I respect him and know that he would bring something to the party.
"He's now got a bit of time to think about it and he will think about it deeply. As he always has done in his life, he will come up with the right decision. I've definitely not given up on it and Alan's not said anything to my knowledge that suggests he doesn't want to do it. I think deep down he does."