Well I don't have a high value of Mervis and i'm also skeptical of his as an MLB regular and always have been. I was against him being on the OD roster last year, but with a year more of experience I see it as a better option than it was last year, but he would platoon at DH at best. At the end of the day whoever makes the cut for that roster spot is going to be last position player on the 26-man.
I'm interested to see what they do at DH vs RHP. There's options like Tauchman, Mervis, Canario, Wisdom, Mastrobuoni, maybe Morel. Later they have Dom Smith and Peralta as options too. They probably go with matchups of bench guys unless 1 or 2 guys start to stand out.