Messi did not feature in Barca's first day of pre-season training under new boss Ronald Koeman on Monday after the six-time Ballon d'Or winner handed in a transfer request.
As with Sunday's coronavirus testing for members of Koeman's first-team squad, Messi did not attend because he believes a clause in his contract allowing him to leave on a free transfer is now active, meaning he is no longer a Barcelona player.
Pep Guardiola's City are believed to be the frontrunners to sign Messi and the Premier League giants have reportedly offered a long-term contract that would end with the 33-year-old playing for sister club New York City in MLS.
Schelotto, whose Galaxy were previously linked with a move for Messi, was asked about the Argentina skipper possibly moving to the United States.
"I was shocked when I heard about Messi's decision about abandoning FC Barcelona because we all thought he was going to retire there," fellow Argentinian Schelotto told reporters.
"But he must have his reasons and as a fellow Argentine I wish him the best always and I hope he comes to the MLS, it would be great."
Messi has called Barca home since 2001, emerging from the club's famed youth system in 2004.