Despite accepting a £6 million deal for Campbell, United have not finalised the deal but Hull chairman Paul Duffen is confident of getting it done.
"The conversations are now with Fraizer's advisers, rather than with the player himself," Duffen told the Hull Daily Mail.
"The negotiations will continue, not withstanding his move to Sweden for the next few weeks.
"We can sign a contract anywhere in the world, that's not an issue. That won't be a barrier to it happening."