Flores, who was born in Canada to a Mexican father and a Canadian mother, is currently in Mexico's camp and preparing for a friendly this Wednesday against Guatemala, which could mark his second appearance for El Tri. The attacking midfielder, who hasn't been cap-tied in an official match, is keeping his options open for now but made clear Mexico would be his first choice if he could play with them in Qatar.
"Canada also wants me, but I think that if Mexico calls me to the World Cup, I think that's where I want to be," said the 18-year-old to TUDN on Monday. "Right now, I don't know, really. I'm thinking and just preparing for when I'm going to make a decision."
Flores said his passion for the sport comes from his father's side of the family and his dad Ruben, who played professionally and also managed the Cayman Islands women's team from 2014-21, but added that no one is pushing him in a certain direction.
"[My dad] doesn't tell me much," Flores said. "He is Mexican and everyone on my dad's side is Mexican. They are very passionate about soccer, they've always loved soccer and they passed that love on to me."
Flores was included in Canada's provisional squad for the 2021 Gold Cup, but took part in the Revelations Cup tournament last November with Mexico's youth national team. In December, he made his senior debut with El Tri in a 2-2 friendly against Chile.
In January, Canada coach John Herdman brought up Flores after a 2-0 win over the United States in World Cup qualifying.
"We've got stars now, we've got young star players that are going to be around for a long generation," Herdman said of Flores. "I'm sure you've got players like young Marcelo Flores [who] might be looking after this game and wondering whether he wants to play for Mexico or Canada. This is what we're starting to provoke across the world."
Mexico manager Gerardo "Tata" Martino said on Tuesday that Flores needs to clarify which side he wishes to represent and that he shouldn't assume he'd be Qatar bound.
"It's difficult to say what the possibilities are for him, what doesn't seem logical to me is that his decision is subject to which team guarantees him a World Cup," Martino said.
At club level, Flores has yet to debut with Arsenal's senior team, but earned praise from manager Mikel Arteta, who said last week he was "developing really, really well." The midfielder watched from the bench during a 3-0 loss to Crystal Palace in the Premier League earlier in April.
Mexico will be without Martino for Wednesday's friendly at Camping World Stadium in Orlando, the Mexican Football Federation (FMF) announced on Sunday. Martino is still unable to travel by plane after an eye procedure last month that saw him miss a World Cup qualifier in Honduras.
The FMF also announced on Monday that Mexico's upcoming CONCACAF Nations League match against Suriname on June 11 will be held in Santos Laguna's Estadio Corona.