Ronaldo almost found the net on his league debut last weekend and Kahn feels the Portuguese will prove to be an excellent acquisition.
Reportedly, the Reds will not allow the 23-year-old forward to leave Anfield temporarily if a mandatory end-of-season purchase option is not included in an arrangement with the German giants.
It is thought Dortmund want to see whether the Belgian can cut it in the Bundesliga initially before weighing up a permanent switch for Origi.
However, Liverpool’s thinking is the opposite – with the Premier League giants wishing to get the former Lille man off their books altogether.
AC Milan are the latest club to have made a move for Paris Saint-Germain midfielder Adrien Rabiot.
Le10Sport claim the Serie A giants want to agree a pre-transfer with the 23-year-old, with a view to the Frenchman arriving at the San Siro in the summer of 2019 as a free agent once his contract expires at the Parc des Princes.
Reportedly, the Rossoneri are preparing a huge financial offer to the player who has struggled to command regular first-team action with the Ligue 1 giants, despite backing from new PSG boss Thomas Tuchel.
In the past months, Rabiot has also been linked with Barcelona, however, speculation has quietened on that front.