The Colorado Rockies designated Dinelson Lamet for assignment on Saturday and recalled fellow right-hander Gavin Hollowell from Triple-A Albuquerque.
The move for Lamet comes one day after he struggled mightily in an 8-1 loss to the Atlanta Braves. Lamet allowed a career-worst eight runs on five hits -- including three homers -- and five walks in four innings.
Lamet, 30, is 1-4 with an 11.57 ERA in 16 games (four starts) this season.
He is 17-24 with a 4.61 ERA in 117 career games (60 starts) with the San Diego Padres and Rockies.
Hollowell, 25, is 0-0 with a 1.54 ERA in nine relief appearances this season with the Isotopes.
He went 0-2 with a 7.71 ERA in six relief appearances last season with Colorado.