Chelsea are considering whether to trigger the €35 million ($38.2m) release clause in Villarreal forward Nicolas Jackson's contract in the coming days, sources have told ESPN.

The 21-year-old is believed to have agreed personal terms on a move to Stamford Bridge and talks between the clubs are expected to progress later this week after Jackson represents Senegal against Brazil on Tuesday.

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It remains possible that Chelsea may try to negotiate a lower fee with Villarreal given Jackson's willingness to leave but the Spanish club would ideally prefer not to sell.

Sources also suggest other clubs have expressed an interest in Jackson. He almost moved to Bournemouth in January before the deal collapsed when the player sustained a hamstring injury. It is understood at least one club in Germany is also monitoring the situation.

New Chelsea boss Mauricio Pochettino is keen to bolster the club's attacking options with Kai Havertz in talks to join Arsenal and Pierre-Emerick Aubameyang deemed surplus to requirements. Jackson can play as a central striker or on the wing. He scored 13 goals in all competitions last season but finished in fine form, netting nine times in his final eight games.

Chelsea are expected to confirm the signing of RB Leipzig forward Christopher Nkunku in a deal worth around €60m ($65.5m) at the beginning of July.