Achraf Hakimi has made a big impression since joining Borussia Dortmund on loan from Real Madrid, but the German side do not expect to sign him on a permanent deal.
The 20-year-old right-back scored his first goals for the club when he netted twice in Saturday's 5-1 win over Hannover, adding to the seven assists he has already made this season.
The Morocco international joined last summer on a two-year loan deal from Real Madrid and has impressed enough to spark talk of a full-time switch to Lucien Favre's Bundesliga leaders.
But former Dortmund star Sebastian Kehl, who is now the head of licencing players at Dortmund, says it is unlikely Madrid will be willing to let him go.
"Unfortunately, we only loaned him for two years and it's going to be difficult to sign him," Kehl told Sport1.
"Real Madrid are also following his development."
While Hakimi's stock is rising at Dortmund, the club are in danger of losing an established fan favourite in Shinji Kagawa.
The Japan international wants to leave before the January transfer window closes, having admitted his desire to play in Spain.
Dortmund sporting director Michael Zorc has said the club are willing to let him go, but Kehl says the situation is heartbreaking for him.
"If I see Kagawa, it hurts my heart," Kehl said when asked about his former team-mate.
"He came to us, he wants to go, he wants to stay in Europe and he prefers a move to Spain, but in the winter break it's difficult to find a suitable club."