Saúl Niguez joined Chelsea from Atletico Madrid but his debut was faulty as he could not cope with the game but sports analysts are monitoring his progress at the club.
Meanwhile, Chelsea striker, Romelu Lukaku, has recommended his former Inter Milan teammates Alessandro Bastoni and Milan Skriniar to the club’s hierarchy, according to Sport Mediaset.
Thomas Tuchel tried to add a new centre-back this summer but the Blues failed to agree on a deal with Sevilla for Jules Kounde.
Chelsea believed they had a verbal agreement with Sevilla over the fee, but the LaLiga side increased that figure by €15million.
Tuchel remains keen to add a new centre-back and could now be looking at Bastoni and Skriniar.
His decision comes following a recommendation from Lukaku, who played with them both at Inter.
A deal for Bastoni would also be tricky, as the Italian international only signed a three-year contract extension in May.
Skriniar, meanwhile, will have just a year remaining on his current contract at the end of the season, which would reduce his asking price.