Hull City must move quickly to tie up a deal for Bristol Rovers teen Alefe Santos.
Sky Sports says Celtic and Derby County are attempting to rumble Hull's deal for the midfielder.
The Tigers have been chasing Santos for months, although they could not agree terms with Rovers and were happy for the deal to go to a tribunal.
With Santos able to sign for a club from Tuesday, Hull had seemed set to conclude a deal but a late move from Derby and Celtic has complicated matters.
