The 26-year-old lasted a season-low 2 2/3 innings in his prior start and on Monday gave up three runs -- including solo homers to Paul Goldschmidt and Welington Castillo -- in the first two frames.
But the lefty settled in after that, allowing just one hit over his final 4 2/3 innings to leave a positive impression and signal another step forward in a season when he's gone 4-4 with a 3.20 ERA in 11 starts while filling in for the injured James Paxton.
"Monty did a nice job," said McClendon.