Chelsea are still pondering a January move for Middlesbrough defender Ben Gibson, according to the Daily Mirror.
The Blues signed former player David Luiz from PSG on transfer deadline day, but manager Antonio Conte is not confident about the fitness of veteran centre-back John Terry and wants to add one more defensive body to his squad.
French centre-back Kurt Zouma is still out with the knee injury he suffered in February.
Gibson has been a key player in the Boro squad for the last three seasons and has played in all of their league games this season.
The Englishman is seen as a long-term replacement for captain Terry.