Leverkusen - European champions Barcelona suffered an injury blow on Tuesday as Brazil star Neymar limped out of training ahead of his side's Champions League clash at Bayer Leverkusen.
"During training this evening, Neymar suffered a small muscle injury in the abductor of his left leg," Barcelona said in a statement ahead of Wednesday's match.
"The development of the injury will determine his availability for the upcoming games."
The 23-year-old is expected to sit out against Leverkusen, but of more concern for Barca is whether he will be ready for the Club World Cup with the Catalans set to play their semi-final in Japan on December 17.
Neymar has been in sensational form this season, scoring 16 goals in 18 appearances.
Earlier on Tuesday he was rewarded for a series of excellent displays by being crowned La Liga's player of the month for November.