Dennis Marshall, a Costa Rican defender, has been killed in a car accident.
Marshall, 25, died along with his wife when his car collided head-on with a truck close to Costa Rican capital San Jose while they were travelling from his grandfather's funeral.
Just five days ago, the AaB defender scored his side's equalising goal en route to a penalty shootout loss against Honduras in the CONCACAF Gold Cup. It was his only international goal in 19 appearances.
A statement from the country's football federation read: "The Costa Rican Football Federation deeply laments the death of the national team player Dennis Marshall Maxwell and his wife Meylin Masis Castro.
"The thoughts of executive committee, selection committee, technical staff and his team-mates, and sporting and administrative personnel of FEDEFUTBOL, are with their families."
National team coach Ricardo La Volpe led the tributes, saying: "It's a tough blow. He was a young guy with a big future and I send my most heartfelt condolences to his family."
Marshall's team-mate Randall Brenes added: "To hear of a team-mate that has died really affects us. It's hit us hard.
"We were in shock hoping that it wasn't him, but it's already been confirmed. It's very sad. He was like a brother to all of us."
AaB later issued a statement on their official website expressing their shock at Marshall's death.
Sporting director Lynge Jakobsen said: "We received the tragic news late last night and are obviously deeply moved by the situation. Our thoughts go first and foremost to their families."
Friday's training session has been cancelled, the club added, while the players will wear black armbands when they face Odense BK in a pre-season friendly next week and during their first two matches of the new season against Brondby on July 17 and AGF a week later.
A minute's silence will also be held before the meeting with AGF, their first home fixture of the campaign.