Born in Burnley in England, the 24-year-old started his career with the local club but failed to earn his senior debut for the Clarets.
He joined Accrington Stanley in 2012 and was handed his senior debut four years later.
He only made the move to Belgium last June, finishing the campaign with 26 appearances and has now been linked with a move back to England.
In fact, a bid of £750,000 from Blackburn has already been tabled, though it falls short of Union SG’s £1m valuation.
The team that finished third in the Belgian Pro League last season, also want to add a sell-on clause in Sykes’ deal.
It now remains to be seen whether Blackburn’s bid for Sykes manages to satisfy Union SG or whether they ask for more.
He has a contract with the Belgian top-flight club that runs until the summer of 2026 and Union SG have qualified for the Europa League.