The Spanish midfielder has been capped by Spain at under-17, under-19 and under-21 level, having joined the Italian club from Atletico Madrid's youth academy in 2008.
He's since gone on to become one of the Serie A club's key players, having made his debut two years ago.
Chelsea boss Roberto Di Matteo is looking to continue the youthful overhaul of his Blues squad with a triple swoop for three of Sampdoria's brightest young stars.
Reports suggest Chelsea are tracking 20-year-old Obiang, 21-year-old defensive midfielder Roberto Soriano and Serbian youth international Nenad Krsticic.
Di Matteo signed two of football's hottest prospects this summer - Eden Hazard and Oscar - and he looks set to continue the Stamford Bridge regeneration in January.
But Chelsea face competition from Manchester City for the signature.
TalkSPORT reported earlier in the week that Roberto Mancini is keen on the young midfielder, and that Sampdoria were willing to sell him for the right price.
Sampdoria sporting director Pasquale Sensibile said to Italian newspaper Tuttosport: "He will only leave Sampdoria for a large offer or when his contract ends."
Obiang's contract expires in June 2015, but if Manchester City or Chelsea tested the water with a high enough offer, Obiang could make the move to the Premier League sooner.