The Ecuador winger fractured and dislocated his ankle in a seemingly innocuous challenge by Rangers' Kirk Broadfoot in United's opening Champions League fixture in September but is on course for a return in late February or early March.
It was feared the severity of the injury would bring a premature end to the season for Valencia but manager Sir Alex Ferguson is delighted with his recovery.
The Old Trafford boss told the official club website: "He's making the progress exactly the way we thought. It's looking like the end of February or beginning of March."
Ferguson added: He should be back training in five to six weeks' time, but given the extent of the injury we'll give him more time to get into the full flow of things."