Iran captain Nekounam was forced to leave the field in the match against Qatar in the 2014 World Cup qualifier in Doha after straining his left hamstring.
The injury will likely keep him out of the team for three or four weeks.
“I have pain in my left foot. I talked to Osasuna’s medical staff and will have a scan on my injured foot after returning to Pamplona. I think I cannot play for three or four weeks,” the 31-year-old midfielder said.
Osauna will host Sporting Gijon in the second game of the season on Sunday. The team will play Barcelona on September 17 at the Nou Camp and Nekounam could miss the important clash.