The 21-year-old stepped in for David Luiz and has since excelled for the Blues. His performances have not gone unnoticed at the Camp Nou, with the Catalan outfit long-term admirers of the Denmark international.
The La Liga leaders continue their search for a top-class defender and Christensen has emerged a realistic target due to his youth and confidence. Umtiti's injury and Mascherano's almost-vertain departure have accelerated the process of recruiting a centre-back.
Chelsea are attempting to extend his deal at Stamford Bridge, which runs out in 2020, to fend off interest from potential suitors. The youngster joined Chelsea from Brondby in 2013 and has been capped 14 times by Denmark.
After returning from a two-season loan at Borussia Monchengladbach, Christensen has certainly impressed in west London. We will have to wait an see if Barcelona can lure one of the hottest young prospects in European football.