Manchester United centre-back Phil Jones has suffered an injury setback during first team training.
The England international was originally out for up to a month, but he now faces an extended period on the sidelines.
Jones has reportedly damage his knee ligaments and has to wear a knee brace whilst he recovers.
The 24-year-old is yet to make a competitive appearance under the new Manchester United boss Jose Mourinho.
Mourinho has promised Jones game time in the cup competitions this season (Europa League, EFL Cup and FA Cup).