Incoming manager Antonio Conte has earmarked the 27-year-old as a top target for the summer, alongside his midfield partner Miralem Pjanic.
But reports in Italy have emerged claiming Nainggolan will not be allowed to leave.
Roma made an early push for the Serie A title this season but fell away by January, which led to manager Rudi Garcia being sacked.
Spalletti filled the void and has rekindled the club's fortunes.
Although they are out of the title race, Roma are closing in on Champions League qualification and want to invest in their squad rather than selling prized assets ahead of the new campaign.
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