Eugenie Bouchard's US Open campaign is in doubt after the Canadian star delayed her practice session at Flushing Meadows.
The 21-year-old suffered a head injury in the locker room after her mixed doubles victory with Nick Kyrgios on Saturday.
Bouchard immediately withdrew from the mixed doubles and women's doubles after the incident, but is yet to make a final decision about whether she will face Roberta Vinci in the last 16 of the singles on Sunday.
The world number 25 postponed her practice session in New York and has not requested any racquets, which has fuelled speculation that she may pull out.
Bouchard was also pictured walking into Flushing Meadows gingerly on Sunday.