According to Sport Bild, Dortmund are keeping close tabs on Ajax midfielder Edson Alvarez and Celta Vigo’s Gabri Veiga ahead of a potential move.
Alvarez’s future has been up in the air for a long time after Ajax blocked his move to Premier League giants Chelsea last summer.
However, there is a big chance that he could be on the move, with the Blues still interested in the Mexican international alongside Arsenal, Newcastle United and Liverpool.
Dortmund have also entered the mix, with Ajax looking for around £40m to part ways with Alvarez. Fellow Bundesliga rivals Bayern Munich are also interested in the 25-year-old.
There have been conflicting reports about Veiga, who is one of the hottest prospects in Europe at present.