Karimi drank water during a training session.
"We do not want Steel Azin without Karimi," the fans shouted during the club's latest game on Wednesday evening.
The club had earlier said in a statement that Karimi had disrespected the rules of the holy month of Ramadan during a training session and therefore had been released.
Following wide-spread protests throughout the country, the Steel Azin management was forced to hold an emergency meeting for discuss the issue again.
No final decision has yet been made.
During the fasting month of Ramadan, Iranian Muslims are not allowed to eat and drink during daytime, including football players who have to train during the day at temperatures reaching 35 degrees without drinking any water.
The dismissal of Karimi, who spent two seasons (2005-2007) in the German Bundesliga with Bayern Munich and was once described as Asia's Maradona, was front-page news in Iran.
He has reived widespread backing though with several former top footballers, including former Bundesliga players Ali Daei and Mehdi Mahdavikia, coming out on his side.
They said that fasting is an individual decision by each Muslim and should not be used as a reason for punishment, especially not in the case of a internationally acknowledged player and skipper of the national team.
The 31-year-old Karimi is one of the most controversial players in Iran.
Last year he wore a green armband in a crucial World Cup qualifier in June last year in Seoul as symbolic support for Iran's opposition.
In 2008, he was dismissed from the national team after harshly criticizing the Iranian football federation and describing its current formation as the weakest in his ten-year spell in the national team, bringing Iranian football backwards rather than forward.
Karimi also voiced criticism against the management of football clubs, saying they were in the hands of officials who knew nothing about football.