The 20-year-old hobbled out of Manchester United's FA Cup fifth round tie with Reading having sustained an ankle injury, and may now miss the second leg against los Blancos
Jones was replaced by Nani in the 42nd minute after sustaining an ankle injury in a tackle with Royals winger Jobi McAnuff, and appeared visibly dejected as he left the field.
The 20-year-old now appears unlikely to be available to feature in the second leg of United's tie with Real, having performed well as a disciplined Red Devils side frustrated the Spanish giants at Santiago Bernabeu on Wednesday.
His absence will come as an untimely blow to Sir Alex Ferguson as he looks to see off Jose Mourinho's star-studded team at Old Trafford and lead United into the Champions League quarter-finals in a fortnight's time.
The full extent of the injury is yet to be revealed but Jones was spotted leaving Old Trafford on crutches, with his leg in a protective boot, after the game.