Ghanim Ghudayer, 22, considered one of the best players in Baghdad's Air Force Club, was kidnapped on Sunday evening by unknown assailants, police said.
Samir Kadhim, the head of the Air Force Club, said Ghudayer had been scheduled to leave for Syria in two or three days to join his new team.
Meanwhile, the US military said two Marines were killed on Sunday in Anbar province, a Sunni stronghold that has seen some of the worst fighting.
Also, a car bomb on Monday wounded five civilians in Baghdad, while in Ramadi, 115km northwest of the capital, gunmen shot and killed Major General Mohammad Thumeil, an officer with Saddam Hussein's military.
The Iraqi defence ministry said on Monday that 15 people believed to be involved in the insurgency had been killed over the last 24 hours by Iraqi army units.