The 21-year-old hitman was wanted by Spurs and Atletico Madrid in the summer but Fiorentina were not convinced by any of the proposals they received.
Negotiations were on for several months over a new contract for the Serbian, but Fiorentina announced earlier this month that the striker rejected an offer of a new deal that would have made him the highest-paid player in the club’s history.
A host of Premier League sides are keen, but Newcastle and Tottenham are claimed to be leading England’s charge.
And according to German magazine Sport Bild, Dortmund have also joined the race to land Vlahovic in the next summer transfer window.
With Erling Haaland is expected to leave the BVB next year, Dortmund are making plans to bring in a replacement for the Norwegian at the end of the season.
And Vlahovic is one of the strikers the club are tracking, along with Red Bull Salzburg’s Karim Adeyemi and Ajax’s Sebastien Haller.
Fiorentina are acutely aware that they are likely to lose the Serbian next summer regardless of his contract situation.
The club are expected to demand a fee of €60m before agreeing to let him go at the end of the season.