Sampson signed a minor-league deal with the Marlins on Monday, Matt Eddy of Baseball America reports.
Sampson had fallen out of the rotation for Arizona's Triple-A squad by June after posting a brutal 6.75 ERA and 2.01 WHIP over 42.2 innings. As a free agent, he chose to return to his home state to sign with Miami, but given his struggles this year, a return to the majors seems unlikely.