Fiorentina are currently leading the chase, according to Gianluca Di Marzio.
Della Rovere joined Bayern Munich two years ago from Cremonese and has since made 46 appearances for Bayern's reserve side in the Regionalliga — the fourth tier of German football — without earning a first-team appearance for the senior squad.
His contract at Bayern Munich runs only to the summer of 2027, creating a window in which the club must decide whether to extend or sell before he becomes a free agent.
The 19-year-old is a left-footed player capable of operating across the attacking line, and has been a regular starter for Italy's Under-19 side.
The prospect of Serie A football — and particularly the development pathway that Fiorentina or Napoli could offer — gives the Italy youth international an attractive alternative to spending another season in German fourth-tier football with no senior Bayern appearances forthcoming.
Di Marzio reports Fiorentina's interest is the warmer of the two, suggesting they have moved with greater intent than Napoli at this stage of negotiations.