West Ham have revealed that Carlton Cole will not require a knee operation but is still set to be sidelined for a 'number of weeks'.
The striker suffered an injury in the 5-3 victory over Burnley and had to be substituted at half-time.
He damaged ligaments but the problem is not serious enough for him to need to go under the knife and the Hammers are hopeful he will return quickly.
"Cole will not need surgery on his right knee and, having been closely assessed in recent days, will start his rehab with the aim of being back as soon as possible," read a statement on the club's official website.
This weekend's match against United precedes crucial games at Birmingham and Bolton, and home fixtures against Chelsea and Portsmouth.
It will come as a major blow to lose Cole for a significant period, with the England international already having netted seven goals this season.
Hammers boss Gianfranco Zola is also set to be without Switzerland midfielder Valon Behrami for around three weeks after undergoing minor surgery on a knee injury, while defender Matthew Upson is struggling with a hamstring problem.