The German international has been linked with a potential move away from the Bundesliga giants with Premier League side Chelsea also tracking the 18-year-old.
A summer deal would suit Barcelona better, due to their financial issues, with the Catalans working on package to offer to Moukoko.
Previous reports from Diario Sport claim Dortmund are in advanced negotiations with Moukoko’s representatives with a decision expected imminently.
“The new proposal is very good and I think Dortmund have a good chance to extend his contract,” he said.
“Dortmund are optimistic, and Moukoko will decide soon. Many European clubs are following the situation, including Barcelona and Newcastle, but Borussia have made their bid.”
Since making his Dortmund debut at 16, as the youngest ever Bundesliga player, Moukoko has continued to smash records, including the youngest Bundesliga scorer and the youngest Champions League player.