Sinisterra has been keen to leave Leeds throughout the summer following their relegation from the top flight.
A clause in his contract allowing him to leave is thought to have expired and it seemed he would be staying put at Elland Road.
Bournemouth are in for him on deadline day though and trying to sign him on loan.
While there has been little noise about the deal from the Leeds end, Bournemouth are confident.
They believe that the Colombian winger will be their player by the time the transfer window closes later this evening.
The Cherries have already pulled off one raid on Leeds this summer.
American midfielder Tyler Adams made the move to Dean Court from Leeds, with the Cherries triggering a clause in his contract.
