Because of the World Cup, Cong Phuong may not play in the SEA Games.

According to the new AFC regulations, Asian countries will merge their 2019 Asian Cup qualifiers to determine which teams qualify for the 2018 World Cup in Russia. The Vietnamese national team, along with 39 other countries, will begin playing in this "double" qualifying round starting on June 11, 2015.

VFF President Le Hung Dung once stated he very much wanted to send the U19 team to the 2018 World Cup qualifiers to gain experience and, to some extent, realize Vietnam's dream of reaching world-class football. However, after the defeat in the 2014 AFF Cup semi-finals, the VFF and coach Miura wanted to use the generation of players like Cong Phuong, Tuan Anh, Xuan Truong, etc., to improve the image of Vietnamese football at the 2015 SEA Games. According to the schedule proposed by host country Singapore, the SEA Games will be played from June 5-16, and the group stage of the football tournament will definitely start a few days earlier.

Therefore, if the VFF decides to call up the U19 team, players like Cong Phuong, Xuan Truong, Tuan Anh, etc., will only be able to participate in one of two teams: the Vietnam U23 team (SEA Games 2015) or the national team (participating in the 2019 Asian Cup qualifiers and the 2018 World Cup qualifiers). Currently, the VFF is also struggling with personnel options for these tournaments, so it's unlikely they know for sure which team Cong Phuong and his teammates will be used in.

Even the question of whether the national U23 team should select the best players in their age group or use the U19 squad as its core is causing heated debate. Both options have their own strengths; for example, using the U19 squad would help Vietnam prepare well for the upcoming SEA Games, while using the U23 squad that impressed at the 2014 Asian Games would give Vietnam a highly competitive team for the tournament in Singapore in June 2015.

Cong Phuong and his teammates are expected to bring a fresh perspective to the Vietnam U23 team and the national team in 2015.

The combined qualifying rounds for the 2018 World Cup and the 2019 Asian Cup will run from June 11, 2015 to March 28, 2016, with the participation of 40 national teams. The participating countries are divided into 8 groups, with 5 teams in each group.

The first two rounds of the qualifiers will take place on June 11th and June 16th, 2015, coinciding with the 2015 SEA Games schedule.

The top eight teams from each group, along with the four best-performing second-placed teams, will advance to the next round (consisting of 12 teams) to compete for qualification to the 2018 World Cup in Russia. These 12 teams will also automatically qualify for the 2019 Asian Cup.

After the 12 best teams qualify for the World Cup, the next 24 teams with the best performance in the qualifying round will be divided into 6 groups to compete for the top two teams from each group to qualify for the 2019 Asian Cup.

Although the Vietnamese national team cannot yet dream of qualifying for the 2018 World Cup, securing a place in the 2019 Asian Cup would still be a great honor.

At the 2015 Asian Cup, the Vietnamese national team was eliminated in the qualifying round, losing 5 out of 6 matches.