The Manchester United defender, 20, failed to win a spot in the full Three Lions line-up for next Wednesday's match with Brazil.
United boss Fergie this week claimed Jones is a better player than former England captain John Terry was at the same age.
And he said: "I am a bit surprised he was in the U-21 squad and not the full one.
"I think the main difficulty with players dropping down is that once they get into the full squad it makes them feel they have achieved something.
"But Phil is only 20 and maybe the idea is to get as good an U-21 squad as they can."