Park said he made the decision due to senior players suffering from fatigue after exerting themselves in domestic and international competitions.
However, the Korean coach still expects his young team to post an impressive score against Brunei.
“Vietnam are in Group B with six teams. It means we will have to play an extra match compared to teams Group A. The teams in Group B are really strong so the result of every match is very important. We have to prepare well for each game and try to do our best,” said Park at a press conference in Manila on November 24.
“We have to play five matches in 10 days. It means that I have to be able to switch my team. More importantly, I have to keep them in top form to achieve the best results in every game,” said Park.
“We will continue evaluating Brunei. We will treat Brunei with respect, but we know we have to score as many goals as possible to give us an advantage in the table.
“I probably won't start my key players, but things might be changed depending on the situation during the match,” he added.
Vietnam always come the Games with their target on gold, while Brunei are usually the underdogs at the regional tournament.
They have lost all 24 matches they have played since 2011, and scored just seven goals.
In head-to-heads between the two sides, Vietnam have won all four games and scored at least six goals without conceding. In their most recent meet, Vietnam beat Brunei 6-0 in March.
Among Brunei's 20-man squad, 12 are between 17-19. Many of them play in junior tournaments while others do not have professional contracts.
Coach Aminuddin Jumat of Brunei said Vietnam were a powerful rival, but people underestimated his team.
"We don't have any pressure on us we'll work hard for the best result,” he said.
The match between Vietnam and Brunei will be aired live at 3pm Hanoi time on VTV6.
Rial contenders
Akari Nishino of Thailand has already criticised the food and training venues, but the Japanese side has apologised to Park for Serbian goalkeeping coach Sasa Todic mocking Park’s height during their World Cup qualifier last week. Todic posted his explanation two days later but his apology was not for Park.
Thailand will face Indonesia is the next fixture in Group B on November 27.
Coach Sundramooethy of Laos said: “We are in a group of strong teams but still hope to go further as we did 10 years ago.”
Laos were the hosts of the 2009 Games which saw their football team advance to the semi-finals for the first time where they lost to Vietnam.
Laos will play Singapore in the last match of the group.
“Group B includes defending champions Thailand and title favourites Vietnam, as well as former winners Indonesia. However, there is still chance for other teams. For Singapore, the first match against Laos is important and we will try our best,” said coach Fandi Ahmad.
All matches will be held at Binan Stadium in Laguna, about 40km from Manila.
