Crossley is set to plead his case to Boro boss Steve McClaren, and ask him to drop his asking price in order to secure a switch to the second city.
The 34-year-old has been offered the chance to challenge for the number one jersey at Birmingham, but Blues boss Steve Bruce is unwilling to match the reported fee of £750,000 that Boro want for the former Nottingham Forest custodian.
Crossley knows that he is destined to be cover for Mark Schwarzer at The Riverside, and needs to be getting regular action to try and win a starting place in the Welsh national side.
"I'm not unhappy at Middlesbrough, but Birmingham have given me a fantastic opportunity," said Crossley.
"I have a real chance to establish myself as their number one and consequently win the number one shirt for Wales back, especially with the Euro 2004 qualifiers to come.
"This could be the last chance for my career to progress."
Former club Forest have also been interested but Crossley is looking to remain in The Premiership, and sees Birmingham as his best chance.
