AS says Isak is among a number of targets that Chelsea could pursue instead, the 21-year-old who has previously been linked with Arsenal is one of the continent's most sought after forwards and has impressed for Sweden at Euro 2020.
The La Real star has a buyout clause of £60million and the LaLiga side insist he will not be sold for less, former club Dortmund did have the option to re-sign Isak for £25m but that agreement was subsequently bought out.
Tuchel had reportedly not been informed that Isak had been signed and left Dortmund a few months later, although he did recognise the Swede's raw talent.
"Alex is a very strong striker, who can play with his back toward goal and is strong in the combination," Tuchel said at the time. "He scores a lot of goals, so it is great to have him here.
"The signing of Isak makes perfect sense. This gives the club a long-term solution for the position of striker. Isak is a very talented player."