The players agent was told that his client had impressed during his brief stint at the Reebok Stadium but despite that Wanderers manager Sam Allardyce wasn't keen to take him on due to his lack of experience in top level football.
"They told my agent they thought i was a good player" said Oliveira.
"However they thought i was a little young at 23 which counted against me... to cut a long story short i'm not going to sign for them" he added
The defender now looks set to sign for Uniao Leiria in his homeland with a permanent switch looking to be very close after Uniao showed strong interest in the player