The 35-year-old Ortiz admitted helping to pick out two rich victims for the kidnappers, said Jorge Domene, government security spokesman for the northern state of Nuevo Leon.
The gang, who said they belonged to a drug cartel, sought an average of 1 million pesos ($73,000) per victim, of which Ortiz received a cut of more than 100,000 pesos, Nuevo Leon's government said.
"I'm speechless," said George W. Grayson, a Mexico expert at the College of William & Mary in Virginia, after the news of Ortiz's arrest. "I suppose it's an indication of the possible ubiquity of organized crime."
Sporting his trademark goatee beard, Ortiz looked impassive as masked soldiers paraded him and three other suspects in Nuevo Leon state capital Monterrey, a city that has increasingly come under attack by organised crime.
Domene said the gang operated by selecting victims at social gatherings, who were then snatched and ransomed.
Nuevo Leon attorney general Adrian de la Garza said the suspected kidnappers were captured on January 5 and noted that the gang's leader, who is still at large, told them they were working for the Gulf Cartel.
The conservative government of President Felipe Calderon has staked its reputation on rooting out Mexico's drug gangs, some of which have branched out extensively into other activities like robbery, extortion and kidnapping.
Ortiz's gang is suspected of more than 20 kidnappings, among them the 2011 abduction of the husband of Mexican pop star Gloria Trevi, Domene said. Kidnapping is punishable by a jail term of up to 50 years, the state government noted.
After Ortiz disappeared earlier this week, Mexican media was awash with speculation he himself had been kidnapped.
The football star, who is currently serving a ban for a doping offence, only helped choose victims and provide information to the gang, whose suspected leader is still fugitive along with several others, Nuevo Leon said.
Between 2007 and 2010 kidnappings in Mexico leapt by nearly 200 percent from 438 to 1284, according to government data.
More than 46,000 people have been killed in the gang violence that has erupted since Calderon began his crackdown on drug cartels soon after taking office five years ago.
The war on the gangs is one of the main issues under debate in the Mexican presidential elections in July.
Drug gangs have long been suspected of corrupting public officials and politicians. Calderon's National Action Party (PAN) has sought to tar the main opposition Institutional Revolutionary Party (PRI) as susceptible to the cartels.
But public probes into sports stars and entertainers for suspected ties to organized crime have been rare.
Nuevo Leon attorney general Adrian de la Garza said there was no indication other football players were involved in the gang's kidnappings, which stretch back at least two years.
Nicknamed "El Gato" (The Cat) for his bright eyes, Ortiz played a single match for the Mexican national side in 2002.
In 2010, Ortiz was suspended after testing positive for anabolic steroids. That ban is due to expire in April.
Famous for his many tattoos and earrings, Ortiz was a longtime regular for top division side Monterrey.
Long seen as the jewel in the crown of Mexican industry, Monterrey has become mired in violence over the past two years as the Gulf Cartel has fought a bloody turf war with Los Zetas, a drug gang that once worked as enforcers for the cartel.
Murder, extortion and kidnapping have spread fear in the city of 4 million people that lies about 140 miles from the Texas border.
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