says the problem is the visa hoops that Iranians must go through.
Team officials told the Memphis Commercial Appeal the visa requirements might well take a lot of time to iron out.
The season is due to begin on Christmas Day. Pre-season matches are already underway.
The Grizzlies have made Haddadi a $2 million offer to return. If he accepts it, he would play for the Grizzlies this year for that sum and then become a free agent at the end of the season next summer, when he could negotiate with all other teams in the National Basketball Association.
There has been some concern as to whether Haddadi would want to return to the United States. He faces a criminal charge in Memphis over beating his girlfriend and she has filed a civil suit against him seeking money.