Paris St-Germain striker Neymar was taken off on a stretcher during their win over Marseille on Sunday night, nine days before their Champions League last-16 second-leg tie against Real Madrid.
The €222 striker appeared to twist his ankle while chasing Bouna Sarr.
PSG beat Marseille in Le Classique with ease, as Kylian Mbappe smashed home the opener and Rolando turned Neymar's pass into his own net for the second.
Edinson Cavani swivelled and fired in a third from Neymar's pass, reports BBC.
“We showed that it’s a very special match for us and we got an excellent result,” Emery said.
“The injury to Neymar was the only negative. We hope it’s nothing serious, but we have to wait for further medical exams.”
The coach said initial tests showed it was a twisted ankle but he added further exams on Monday would reveal if there was more serious damage, according to a Reuters report.
Paris St-Germain - who are 14 points clear of second-placed Monaco in Ligue 1 - host Real Madrid on Tuesday, 6 March, trailing 3-1 from the first leg.
Neymar has scored 29 goals in 30 games since his world-record move from Barcelona in the summer.