York City manager told the York Evening Press
"A loan fee has been agreed and a price agreed in principle if they want to make it permanent. It's a way of unlocking the door to give Lee his opportunity and, with our financial situation, it will clearly help us to hopefully go out and get the striker we want.
"He's been a tremendous servant and that's why we have given him this opportunity. This is how we have to work things now."
Brass is sure City will make Bullock a permanent signing in the summer.
"Tomorrow night looks like it might be Lee's last game for us and I am sure he will want to sign off with a bang as he has come through the ranks here and has a strong affinity with the club."
A fee believed to be an initial £75,000 has been agreed and will be paid if Cardiff want to keep Bullock in the summer.
Bullock will be eligable to take part on Saturday against Norwich if selected.
Lennie Lawrence has been linked with a move for Bullock for a couple of months and the 22 year old was closew to signing in January.
He has started 155 league games for York City and this season has scored 7 goals. In total with cup and subs appearances he has racked up 188 matches.