The 21-year-old has established himself as one of the world's top prospects over the past couple of seasons, and Upamecano has been widely linked with a host of top European sides.
With Manchester United supposedly looking to bolster their defensive ranks before the transfer window closes on October 5, the Red Devils are thought to be at the head of the queue for Upamecano's signature.
Ole Gunnar Solskjaer's side could now look to step up their pursuit of the highly-rated Frenchman, with Croatian outlet Sportske reporting that Leipzig have agreed a deal with Dinamo Zagreb for teenage defender Josko Gvardiol.
The report claims that Leipzig and Zagreb have reached an agreement over a £17m fee for the 18-year-old, who was also on the radar of Leeds United.
While Gvardiol's proposed arrival could see United be given the green light to move for Upamecano, Leipzig manager Julian Nagelsmann has previously insisted that the Frenchman will be staying put in Germany for the time being. body check tags ::