Volkswacht Bodensee - Messi starts his new job in the Florida heat

The Argentine World Cup winner took to the club's training field at 9:00am local time with temperatures already above 30 degrees Celsius (86 degrees Fahrenheit).

Along with his former Barcelona team-mate, Spanish midfielder Sergio Busquets, who signed for Miami on Sunday, Messi was given a 'tunnel' welcome from his new team.

The players lined up opposite each other and Messi and Busquets ran through the 'tunnel' to applause and slaps on the back from the other players.

The pair will soon be joined by a third former Barcelona veteran with Spanish full-back Jordi Alba joining the club.

"Jordi Alba will sign today," club co-owner Jorge Mas told reporters.

Chatting with Venezuelan international Josef Martinez, likely to be his strike partner for Miami, Messi was watched by over 200 media representatives who had attended the session as he did some basic drills.

Miami's training sessions had barely attracted double figure attendance from the media before Messi's arrival.

Messi was unveiled to the club's supporters at the stadium on Sunday, at a celebratory event alongside Miami co-owner David Beckham. The Argentine's first game is scheduled for Friday.

Miami, who are ranked last in the 29-team MLS, face Mexican club Cruz Azul in the opening game of the new Leagues Cup, a competition featuring all top-flight teams from MLS and Mexico's Liga MX.

It is not clear yet if Messi will start that game or make an appearance from the substitute's bench. His coach, fellow Argentine Gerardo 'Tata' Martino has asked for patience while the 36-year-old builds up his fitness.

Miami co-owner David Beckham said any decision on Messi's involvement would come down to Martino and Messi himself, but also hinted at only partial involvement for the star.

"Leo will play some part of the game but that will be down to the coach (and) it'll be down to Leo to decide if he's ready because we know that he's been away for a few weeks with his family but he looks sharp, he looks great but you know he's gonna need time to adapt as well," said Beckham.

Messi played his last competitive game for Paris Saint-Germain in the French league on June 4 and then turned out for Argentina against Australia in a friendly in Beijing on June 15, scoring after just 79 seconds in a 2-0 win.

- Biggest star since Pele -

The MLS season runs from late February to the end of October, followed by the playoffs and the championship game, MLS Cup, on December 9.

Despite sitting rock bottom of the Eastern Conference with the worst record in the league, Miami are not mathematically out of contention for the playoffs but it would take a huge impact from the seven-times Ballon d'Or winner to turn their season around.

Messi is the biggest star to join an American club since Brazilian legend Pele moved to the New York Cosmos in 1975.

MLS hope that his presence will massively boost interest in the league, which features clubs from the USA and Canada, and generate fresh revenue for their broadcast deal with Apple TV.

MLS's 10-year deal with Apple TV, worth a reported $2.5 billion, will allow fans in 107 countries to watch Messi in action via a subscription.

On Sunday, MLS Commissioner Don Garber said the league, which is already broadcast in Spanish and some games in French, was considering introducing other languages to broaden the appeal of the broadcasts and cash in on interest in Messi.

"I think you'll see more and more multiple languages on Apple. That's the uniqueness of the technology. We're looking at launching other languages as early as next year," he said.

"I think there will be more opportunity for us to be very, very targeted to specific audiences," he said.

O.Lorenz--BTB