The defender has an agreement in place with Dortmund and has been keen to move to the Westfalenstadion this summer.
Negotiations between Southampton and Dortmund have stalled with the German giants feeling that Saints are asking for too much money.
Dortmund are close to calling off their pursuit of the Southampton centre-back on deadline day.
According to German broadcaster Sky Deutschland, the defender is also not optimistic about the move happening today.
The talks between the two clubs have stalled and the defender is no longer certain that Dortmund will try to revive the deal.
BVB have already committed to spending €15m on new signing Niclas Fullkrug, who joined on Thursday.
It is unclear now whether they have the budget to try and sign Bella-Kotchap on deadline day.
Unless there is a sudden change in the final hours of the window, the defender is set to stay at Southampton.
