Marlins acquire Starling Marte from D-Backs for Caleb Smith
Class-A left-hander Julio Frias is the third player going to Arizona in the deal, a source told The Athletic's Ken Rosenthal.
Marte is in the midst of a stellar campaign. The 31-year-old is hitting .311/.384/.443 with eight doubles, 14 RBIs, and five steals this season. The Diamondbacks acquired him in January from the Pittsburgh Pirates, with whom he spent the first eight years of his career.
The veteran outfielder is owed the remainder of his prorated $11.5-million salary for 2020 and has a $12.5-million club option for 2021.
Smith, 29, has made only one start this campaign after testing positive for COVID-19, but posted a 4.52 ERA and 1.23 WHIP in 28 starts for Miami in 2019.
The 23-year-old Mejia appeared in three games for the Marlins this season, recording a 5.40 ERA and 6.93 FIP. He managed a 2.09 ERA and 0.90 WHIP last year in 18 minor-league appearances, 14 of which were starts.
Frias, 22, pitched well in the minors in 2019, posting a 2.83 ERA with 73 strikeouts in 70 innings.