The headaches started last year when the US Treasury Department accused El Tri's longtime captain, Rafael Marquez, of being a “front person” for an international drug-trafficking organisation.
And they got worse on June 5, when gossip magazine TVNotas reported that nine members of Mexico’s World Cup squad had an all-night party with a group of 30 prostitutes after their farewell home match that weekend.
The Mexican Football Federation decided against punishing the players, because “they have not missed training” and “a free day is a free day”, in the words of general secretary Guillermo Cantu.
But the public condemnation and online mockery have been blistering.
“The federation doesn't have to punish the party-boy players. The public and private ridicule will be more than enough,” sports journalist David Faitelson of ESPN wrote on Twitter.
As the scandal swirled, midfielder Hector Herrera asked for a leave of absence from training in Denmark to travel to Portugal, where he is based, and tend to “personal matters”, according to media reports.
Trying to calm the storm, star striker Javier “Chicharito” Hernandez posted a video online that he said proved the team “didn’t do anything bad” – though he admitted, “I don’t think we’d do it again.”
The controversy echoes similar scandals around the team in recent years.
In September 2010, Mexico players had an all-night party in their hotel with unidentified women after a friendly.
On that occasion, the federation fined 11 players and slapped six-month suspensions on defender Efrain Juarez and forward Carlos Vela.
In June 2011, before a trip to Argentina for the Copa America, Mexican players hired sex workers in a hotel in Quito, Ecuador. They were fined and suspended from the team for half a year.
The latest chapter has particularly outraged some die-hard fans, who worry the scandal will distract the team going into their high-stakes opening match against the world champions.
“The scandal will affect the family life of those involved, their relationships with their teammates and their performance at the World Cup,” said Mexican writer Juan Villoro in a scathing newspaper column entitled “Locker-room anthropology”.
Other fans take the view that in football, as in love, it is best to forgive and forget.
“I’m with my Mexico, just like during every World Cup,” said Alfonso Avila, a 37-year-old fan.
“I hope when the team starts delivering results that all those people who criticised them aren’t going to try to jump on the bandwagon.”
So will El Tri be distracted by the noise?
AFP asked veterans of the Mexican national team to weigh in.
“I think it will distract them, and I think a lot of the players will have family problems,” said Manuel Negrete, a member of Mexico’s 1986 World Cup squad.
“They need to be extremely concentrated on the one-on-one against Germany.”
But there is nothing new in footballers behaving badly, said 89-year-old Antonio “Tota” Carbajal, a five-time World Cup veteran.
“This isn’t the first team to go through this. I went through it myself,” he said, recalling an incident from the 1966 World Cup in England, when two players snuck out of training camp to go to a bar – and coach Ignacio Trelles followed them to drag them back.
This year’s squad “did a stupid thing, you can’t deny it”, he said.
“But these things unite the team.”
The bigger problem may be longtime leader Marquez’s legal woes.
Marquez, who was the team captain for years, is playing in his fifth World Cup, and coach Juan Carlos Osorio says he is counting on his leadership.
But the 39-year-old arrived in Russia under the cloud of an ongoing drug trafficking investigation that cost him sponsors and forced him to take a nearly three-month break from football last year to focus on his legal defense.
“He’s a guy whose leadership will be very necessary at the World Cup,” said former national team member Joaquin Beltran.