The Ecuador striker has attracted interest from the London club following his performances at the World Cup, and arrived in the capital yesterday to undergo a medical.
The defender told The Mirror: "We can't rely on Andy all season. He was the big signing last season, but Andy struggled with injuries so hopefully the new signings will take the pressure off him a little bit.
"And from what I've seen of Valencia against England, he looks a very good player. He can nick a goal and it is competition for places. It's what we've needed as we didn't have that last season."
It is thought that the Pachuca forward will cost West Ham around £12m.