Brighton are hopeful of keeping Marc Cucurella after rejecting City's opening £30m offer.
Though Cucurella - who turned 24 on Friday - is keen on a potential switch north, City are some distance from meeting Brighton's £50m valuation.
It means the Seagulls remain optimistic that their star defender will remain on their books for the start of the Premier League season in a fortnight's time.
The Spain international made 35 appearances for Brighton last season, following his £15m move from Getafe. He signed a five year contract, and the Seagulls have ambitions to hold onto their man for a little while longer - unless City stump up.