Paraguay's top footballer Salvador Cabanas was in critical but stable condition on Monday following surgery in which doctors failed to remove a bullet lodged in his skull.
Dr. Ernesto Martinez, who was part of the surgical team, told reporters he could not say that the Paraguay striker was out of life-threatening danger, but he called his condition stable.
Cabanas, expected to lead Paraguay when the World Cup opens in June, was shot in the head in a pre-dawn attack on Monday at "Bar Bar," a popular nightspot in a well-off Mexico City neighborhood.
"We cannot guarantee that his life is out of danger," Martinez said.
"Injuries like this are unpredictable," he added. "We don't know what kind after effects he might have - perhaps none, or perhaps there will be many. We don't know right now."
Mexico City Attorney General Miguel Angel Mancera, after visiting the bar, said that robbery did not appear to be the motive in the attack on the forward who plays for Mexico City club America.
"At this moment we do not think the motive was robbery because nothing was taken," Mancera told reporters at the crime scene.
America club president Michel Bauer said Cabanas was conscious when he arrived at the Mexico City hospital and was speaking as he prepared for surgery to remove a bullet lodged in the front part of his skull.
"He was a bit confused and didn't know what had happened and he was asking where they were taking him and why they were taking him there," Bauer told Mexico television Televisa.
Bauer said Cabanas' wife told him the two were preparing to leave the bar when the shooting took place in a bathroom. His wife said she found her husband on the bathroom floor.
Mancera told reporters that four people were being questioned, two security guards and the manager of the bar, and a fourth person he identified as Cabanas' brother-in-law. He said the brother-in-law volunteered to testify.
Cabanas, 29, has played in the Mexico league since 2003 and is the highest profile player on the Paraguay national team, which will face Italy, New Zealand and Slovakia in the group stage of the World Cup in South Africa in June.
Cabanas has scored 125 goals in 218 matches in Mexico. Earlier this month he attracted the attention of Sunderland manager Steve Bruce, who expressed interest in bringing Cabanas to the Premier League club. Reports suggested the deal may have fizzled because America's asking price was too high.
"Club America is deeply sorry for what happened to our beloved Salvador Cabanas and shows its total support for his family and loved ones," the Mexican club said in a statement.
Cabanas played over the weekend in America's 2-0 loss to Morelia.
Paraguayan Football Association president Juan Angel Napout said a doctor would travel to Mexico to aid Cabanas in his recovery.
"We are praying for him," Napout said.
Cabanas was named the South American football player of the year in 2007 by Uruguay's El Pais newspaper, the only time a player in Mexico has won the award.
There is a long history of violence involving Latin American football players.
In probably the most notorious case, Colombia defender Andres Escobar was shot and killed in Colombia only days after his own-goal helped the United States defeat the Colombians 2-1 in a major upset at the 1994 World Cup.
