The Texas Rangers are expected to go into the 2018 season with a six man rotation. Cole Hamels, however, is apparently not a fan. In comments tweeted by the beat guys, Hamels rips the six man rotation, saying "it's not a part of baseball" and "you may as well be in college," while also saying it's "not appropriate" for where he is at this stage of his career.
We shall see how serious these concerns are, how dug in Hamels is on his anti-six-man views, and how committed the Rangers really are to this experiment. One would assume that the Rangers will likely use Hamels on a more normal schedule than some of the other pitchers, and there's been some talk that if Mike Minor and/or Matt Bush make the rotation, they could see their turns skipped occasionally as the team works to manage their workload.
That said, if Hamels is really unhappy about being in a six man rotation, things could get uncomfortable quickly. Hamels has a $20 million team option in 2019, and I suspect he doesn't want to be in a position where he is perceived in a potential contract year to be unable to handle a regular workload. This is probably not a big deal at this point, but it's something to keep an eye on.