Manchester City will give Alfie Haaland four months of intensive physio to salvage his career at the club.
The Norwegian midfielder was told recently that he was being put "on notice" by the club after an injury-plagued two years threatened to bring his career to an end.
Haaland was upset by the move and brought in the Professional Footballers' Association to act on his behalf in a bid to get the decision overturned.
But Keegan believes the club have only acted in their best interests and has challenged Haaland to prove them wrong.
"If Alfie can prove his fitness there will be no problem with this club," Keegan said.
"We aren't saying we don't want him, we want him to come back. We are all behind him and will give him our full support. But he has to prove his fitness and so far that hasn't happened".
PA