Rojas was a tough one for sure.
As everyone has speculated, the Jays must be considering the possibility of trying the starter route again or they see a high likelihood of Varland continuing to perform as a high leverage reliever.
Before a certain someone goes on a rant, everyone here knows that relievers have greater variability. Greater variability does not mean complete randomness - relievers with great stuff and a younger age are still very valuable, just look at the multi-year contracts that educated GMs are signing high-end relievers to in free agency.
The Jays probably see Rojas as a likely high leverage reliever and valued the Varland control years x probability of performance > Roja's control years x probablity of performance and have dramatically lowered expectations on Roden in a show-me year given he turns 26 soon. At the end of this year, I suspect Roden will have fallen way down the prospect rankings. It's disappointing because I had high hopes for him at the beginning of the year, but prospects usually break your heart.