Club sources suggest the club have ready to chase in on the striker, having previously had a bid of £6.4 million rejected.
The likes of Zenit St Peterburg and Liverpool are reportedly in contention, but Chelsea are the club leading the race.
Chelsea scout Piet de Visser is said to be in the Chilean capital to begin negotiations for a deal for the 21-year-old, who was on the verge of joining Liverpool earlier this year.
The Reds got one over Andre Villas-Boas' side earlier in the season, beating them in the league and in the Carling Cup at Stamford Bridge
Both Chelsea and Liverpool, who will be battling for a top four spot in the Barclays Premier League, are also fighting for Barcelona's David Villa.