It has been reported that West Ham manager Slaven Bilic is happy to let Valencia leave as the Ecuador international does not feature in his plan for the 2017-18 campaign.
The 27-year-old spent last season on loan at Everton, but the striker failed to make a huge impact at Goodison Park.
Valencia was able to make only five starts in the Premier League for Everton last season, scoring three goals and providing one assist in the process.
The striker has failed to do much of note at West Ham since his move from Pachuca in 2014 for a transfer fee reported by The Sunday People (print edition, page 58, June 18, 2017) to be worth £12 million, and it would make sense for him to leave the London Stadium in the summer transfer window.
Returning to Mexico would be a good decision, as Valencia knows that league well and could revitalise his career and get a lot of playing time.