MLS reviewed the incident, which occurred on Saturday and was captured on video, and determined the area Messi entered was not the referees' locker room, nor was it a restricted area, and therefore no policy was violated, the spokesperson told Reuters.
In the video, Inter Miami's Luis Suarez is seen attempting to restrain Messi by the arm but the Argentine still managed to walk through the doorway in the bowels of the Los Angeles Memorial Coliseum before re-emerging moments later.
The spokesperson said restricted areas at the venue would have had clear signage.
Inter Miami did not immediately respond when asked by Reuters for comment.
Defending champions Miami opened the season with a 3-0 loss in a game that drew 75,673 fans and was the highest-attended match in MLS opening weekend history.