QPR's Grant Hall has suffered a setback in his return to fitness after injury.
The defender featured in his second under-23s game of the season, playing 70 minutes of the 5-4 victory over Charlton Athletic on Monday.
It appeared that the 25-year-old was within a couple of weeks of a first team return, something which now may not be the case.
Speaking to the club's website, manager Ian Holloway said: "Hally has had a setback.
“He couldn’t train this week because he had a reaction after the game. We don’t know the seriousness of it at the minute. Hopefully it will settle down but there was no reaction to his first game but there has been a reaction to his second one.”