The Bushehr based club confirmed the news on Saturday.
“Karimi has told us he wants to leave the team since he suffers from disease,” Shahin general manager Mehrdad Mohammad-pour said.
Former Damash coach Ebrahim Ghasempour will more likely replace Karimi at Shahin.
Shain is second from bottom in Iran Professional League (IPL) with 25 points.
The team is scheduled to face Esteghlal on March 5 in Iran’s Hazfi Cup final.