Gil was expected to return to VCF after last season's loan, but the market shut with the Spaniard still in London.
Gil will now provide cover for the likes of Heung-min Son and Dejan Kulusevski in attack.
Following reports of the player's loan deal to Valencia collapsing, the ex-Sevilla man took to social media and posted a cryptic message in Spanish on his Instagram Stories.
It read: "Sometimes an old photo makes us value moments where we were happier and didn't realise."