His Mexican club Pachuca confirmed they had already received bids for the striker.
Pachuca's vice-president Andres Vassi admits: "Enner Valencia's value increases every day. We don't know if he will stay, it will be hard given the offers we have received.
"The options that a great player at this level gets are to be taken into account. But for now he has to keep doing things right.
"No doubt it would hurt us to let Enner Valencia go, but we are realistic about his quality."
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