Messi will return to Inter Miami after leading Argentina into Sunday's World Cup final against Spain at MetLife Stadium, and Garber expects the eight-time Ballon d'Or winner's global profile to give MLS another major boost.
The league has already experienced the "Messi effect" since his arrival in Miami three years ago, with crowds, television audiences and worldwide interest all increasing.
Garber admitted he never imagined an MLS player would be starring on football's biggest stage before returning to league action.
"None of us in the league understood what Messi was when he was playing at Barcelona, other than as fans," Garber said.
"The fact that he would have a right-footed cross at the last moment and be able to win a game in front of the world and be in the final, and then take off his Argentina jersey and put on an MLS jersey. I never dreamed that that could happen."
Messi produced two dramatic late assists in Argentina's semi-final victory over England, adding to his remarkable World Cup campaign and increasing the excitement ahead of his return to Inter Miami.
Garber believes the World Cup, being hosted in North America, will help drive the next stage of MLS growth by attracting new fans and inspiring more young players to take up the sport.
The league has also continued to strengthen its profile by signing established international stars, including former Atletico Madrid forward Antoine Griezmann, who recently joined Orlando City.
Griezmann believes MLS has improved significantly in recent years and expects the World Cup to leave a lasting legacy.
"The World Cup also helps so all kinds of American kids can enjoy soccer and want to start kicking a ball," Griezmann said.
"Hopefully, we can put on a show in the stadiums to make kids want to play soccer."
Thibaut Courtois believes Belgium have appointed the right man after Mark van Bommel was named the national team's new head coach, with the Real Madrid goalkeeper praising the former Netherlands international's experience and leadership.
Coach Roger de Sa believes Ghana can take pride in their performance at the 2026 FIFA World Cup, but admits the Black Stars were left wondering what might have been after a controversial goalless draw against England.
Cape Verde goalkeeper Vozinha is set to join Chilean giants Colo Colo after reaching an agreement with the club following his outstanding performances at the 2026 FIFA World Cup.
Belgium have confirmed the appointment of Mark van Bommel as their new head coach following the departure of Rudi Garcia after the 2026 FIFA World Cup.
