The Blues are set to be snubbed again by top target Leonardo Bonucci, who is expected to sign a new deal with Juventus instead.
And all attempts to bring in Alessio Romagnoli have so far been blocked by AC Milan.
A move for Tomovic, 29, would be a surprise as the Serb has struggled at times this season and is no longer a regular for his country.
But Conte appears to like his versatility as he can play at full back as well as in a back three.
And he would provide experienced cover as a cheaper alternative to more high-profile targets.
Chelsea failed with bids for Bonucci, Romagnoli and Napoli’s Kalidou Koulibaly in the summer but are still looking for another defender despite bringing in David Luiz.
