Verlander has not pitched for the Astros this season due to shoulder inflammation.
The Padres made the retroactive move ahead of their game against the Brewers in Milwaukee.
Following a surprise trip to the playoffs in 2023, the Marlins are in a downward spiral, with their manager's option for 2025 voided.
The three-time Cy Young Award winner opened the season on the injured list with inflammation in his right shoulder.