Collmenter ended his season allowing one run on three hits and three strikeouts in eight innings in the Diamondbacks' 1-0 loss to the Cardinals. It was a great start, but he still managed to get the loss. He ended the season strong, allowing seven runs in his last seven starts. In that span, he went at least six innings in each start. As a result of the good finish, his ERA moved to 3.43. He finishes the season with an 11-9 record.