The Bulls had announced the signing of Platt in October after the Tigers’ relegation from the engage Super League, but Castleford demanded a transfer fee as the player had no release clause in his contract.
A Rugby Football League tribunal ruled that Bradford did have to pay a transfer fee in order to obtain Platt’s services, hence today’s deal between the two clubs.
"We wish Michael well," said Tigers chief executive Richard Wright. "He has done a good job for us in his two years here and was a stand-out player in 2005 helping us to promotion for which we thank him.
"We paid a small fee for him when he came from Rochdale which we have recovered and also received some compensation for his development."
Platt will be replacing Michael Withers at Odsal, as the previous Bradford full-back has made the switch to Wigan Warriors.