Melville had his contract selected from Triple-A Albuquerque on Wednesday and is starting against the Diamondbacks.
Melville will join the big-league rotation in place of Jon Gray (foot), who landed on the injured list ahead of his scheduled start Wednesday against Arizona. The 29-year-old right-hander owns a lackluster 5.42 ERA, 1.58 WHIP and 94:40 K:BB in 96.1 innings with Albuquerque this season, so it would be unwise to expect much from Melville in what will be his first big-league start since 2017.