Hawk Wing, brilliant winner of the Juddmonte Lockinge Stakes at Newbury on his reappearance, may soon be retired from racing.
On his only subsequent start Aidan O'Brien's enigmatic performer finished a disappointing seventh of 10 behind Dubai Destination when sent off at 8/13 for the Queen Anne Stakes at Royal Ascot.
However, it was later discovered that Hawk Wing had strained the check ligament at the back of his near-fore knee.
O'Brien had been planning an autumn campaign for the colt but the son of Woodman has not been recovering as well as connections had hoped.
"Things are proving very difficult with Hawk Wing and we will probably make a decision on him in the next week," O'Brien told the Racing Post.
"He did well in the couple of weeks after Ascot but he then stopped responding to treatment."
Hawk Wing was a fast-finishing second to stable companion Rock Of Gibraltar in last season's 2000 Guineas before occupying the same position behind another O'Brien inmate, High Chaparral, in the Vodafone Derby.
He then won the Coral-Eclipse at Sandown but was subsequently beaten at odds-on in both the Irish Champion Stakes and Queen Elizabeth II Stakes.
Hawk Wing appeared better than ever on his return when trouncing his QEII conqueror, Where Or When, by 11 lengths before picking up the injury at Royal Ascot.