WILL Hughes is out of Derby County's tough-looking Championship clashes against promotion chasers Crystal Palace and Cardiff City.
The 17-year-old midfielder is sidelined with a groin problem.
He missed the last two matches and Derby have not put a time scale on his return, saying they will not bring him back until he is fully fit.
Derby, without a win in five games, face Palace and Cardiff in the space of five days.
Fourth-placed Palace visit Pride Park on Friday night and the Rams travel to take on leaders Cardiff on Tuesday.
Nigel Clough admits that they missed Hughes in the draw against Bolton Wanderers and in the defeat at Watford.
"There has been no real improvement in the injury and, as much as we want Will back on the pitch, the bigger picture comes into view. We have to make sure he is right," said the manager.
"If he was a 28 or 29-year-old professional, we would be patching him up and getting him back on the pitch but we do not want any long-term effects.
"We will give him as long as he needs and we will make sure he is right."
Derby believe the groin problem is down to the demands of the youngster playing 35 matches in what is his first season at senior level.
Hughes has made a huge impact in Clough's team.
"We missed Will at Watford, as we did against Bolton," said Clough. "Watford was the sort of game where you wanted somebody to get a foot on the ball and create, or thread a pass through."
Derby used a 4-3-3 formation on Saturday with Craig Bryson, Jeff Hendrick and Paul Coutts as a midfield trio.
"The three did OK in there but they gave the ball away too much," said Clough.
"We gave the ball away much more than we have done in recent games.
"All three were culprits, and they gave it away when there was nobody near them.
"It was a bit sloppy at times."
