David Beckham believes Lionel Messi will need time to adapt to Major League Soccer, even though the standard of play is at a "different level" from the European game.

Inter Miami co-owner Beckham, the former Manchester United and Real Madrid midfielder, watched Messi take part in his first training session for the club on Tuesday after signing a two and a half year contract.

Spanish midfielder Sergio Busquets, a former team-mate of Messi's from Barcelona, also trained at the club's complex, after signing on Saturday, with former Barcelona and Argentina coach Gerardo 'Tata' Martino leading the session.

"Leo's still going to need, no matter how good he is, no matter what his stature is, he and Sergio are going to need time to adapt no matter," said the Englishman.

"They might surprise us, we might start winning every single game, but we have to be patient," he said.

Miami's fans may need to show that patience at Friday's Leagues Cup game against Mexicans Cruz Azul, with Beckham saying the Argentine may not necessarily start.

"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 he's going to need time to adapt as well," said Beckham.

Beckham was the biggest name to have moved to MLS when he signed for the Galaxy in 2007 when the league had just 13 clubs, compared to 29 today and the standard of play was significantly lower.

But Beckham said that there was one area where nothing had changed.

"One of the similarities will be, when I came, all of a sudden, everyone thought: LA are going to win everything. LA are going to win every game, 7-0, 8-0, and that's it, nobody else is gonna win anything," he said.

But despite Beckham's arrival, the Galaxy weren't even able to make the playoffs in his first two seasons.

LA finished next to bottom of the Western Conference in 2007 and 2008 but then in 2009 were beaten finalists before winning MLS Cup in 2011 and 2012.

"Those first two years for me, it was a challenge, getting used to everything, bringing the club and the league to be a little bit more professional, but things changed very quickly," he said.

"I started enjoying the soccer a lot more, not just because we were winning (but) because I could see the change that was being made -- the academy stuff coming into each of the clubs... we're now at a stage where things are definitely different to how they were in 2007," he said.

While the standard of MLS is still well below that of the top leagues in Europe, where Messi has spent his entire club career, several foreign players who joined the league late in their career have found it difficult to thrive.

The frequent travel across time-zones, playing on artificial surfaces at some stadium, and having team-mates who might not be on the same wavelength or have the expected technical ability, are some of the challenges players have faced.

Beckham has no doubt that Messi will be a success but accepts his impact on the field might not be as instant as some may be anticipating.

"It's a different style of football, it's  a slightly different level to what obviously some of the players that are coming in are used to," he said.

"But at the end of the day, this level of football in this country now is a good level, it's a great level, so there are going to be moments where we have to be patient," he said.