Supple is regarded as one of the top young keepers in the country, but won't be allowed to leave Portman Road easily. He broke into the first team last season and made 23 appearances for the Tractor Boys.
Bennett's departure left Leeds without any experienced cover for first-choice Neil Sullivan although trialist Darren Ward played in last night's friendly at Grimsby.
The funds available through the sale of Bennett and Rob Hulse, who also moved to the Blades and Joel Griffiths who has gone back to Australia, have however, assisted Kevin Blackwell's muscle in the transfer market.