Inter Miami star Messi misses training ahead of US Open Cup final
The final represents a chance for Miami to win their second trophy since Messi joined the club, adding to their victory in the Leagues Cup last month.
Messi missed Miami's 1-1 draw at Orlando City on Sunday with coach Gerardo Martino saying that his status is "day to day".
It remains unclear whether Messi is simply struggling with fatigue after a hectic schedule since joining the club in July or whether he is carrying some form of injury.
Martino has referred to old "scars" that are hampering the player but there has been no mention of any specific injury.
Martino is due to address the media later on Tuesday where greater clarity could be provided as to whether Messi will feature in the game.
Inter's training session was open to the media for the first 15 minutes and neither Messi not his former Barcelona team-mate Jordi Alba were involved in the session.
The seven-times Ballon d'Or winner has been struggling since he was substituted in the 88th minute of Argentina's World Cup qualifier against Ecuador on September 7.
He sat out the world champions' second qualifier, at Bolivia, five days later before returning to his club after the international break.
Messi then missed Miami's 5-2 defeat at Atlanta on September 16 with Martino saying that he was suffering from muscle fatigue.
He then started the home game against Toronto but had to be substituted in the 38th minute, just minutes after Alba had been withdrawn.
Alba also missed the Orlando game and is a strong doubt for Wednesday's match.
After Sunday's 1-1 draw in the Florida derby, Martino was non-committal about Messi's chances of facing the Dynamo.
"It is very difficult to put a percentage as to what the chances are that he could play because we are taking it day by day," Martino said.
"We will evaluate him, and I will first listen to what he says as to how he feels. We then have to evaluate what the future risks are," he added.
After the final, Miami have five games remaining in the MLS regular season as they seek a late push into the playoff positions.
On Saturday, Miami host New York City FC who currently hold the last playoff qualification spot, ninth place, five points ahead of Martino's team.
The U.S. Open Cup, a knockout tournament for amateur and professional teams, has been competed for since 1914 making it by far the oldest soccer competition in the country.
