If that is the eventual outcome I certainly won't be upset, but I continue to think it's a mistake to not give him starts from Day 1. The 2018 rotation is currently Lester, Hendricks, and mystery, and by hamstringing Montgomery with relief appearances you lower the certainty that you know 2018 Montgomery 1) is a guy you want in the rotation and 2) can handle a SP workload. There might come a point where they need to prioritize 2017 success over that 2018 certainty, but Opening Day certainly isn't that time. The fact that there's only one lefty isn't a big deal, it's that it's Montgomery. Like David said, Uehara has reverse splits(especially last year), plus Davis, Strop, and Edwards are all quite good against LH hitters. With only one LHRP you'd want to use them in a specific situation, which means Montgomery's multi-inning ability isn't a great match(plus he should be starting anyway). I forget exactly where I read it, but apparently MLB has told teams they're going to require increased documentation on injuries for DL stints, to avoid such shenanigans with the 10 day DL. No idea how strict they might be on that front though.