Both moves were made Thursday and are retroactive to March 26. Trumbo has a right quadriceps strain and Ynoa has a shin injury.
The Orioles also selected the contracts of four players from Triple-A Norfolk: infielders Pedro Alvarez ($1 million salary in major leagues) and Danny Valencia ($1.2 million), and outfielders Craig Gentry ($900,000) and Colby Rasmus ($3 million).
Alvarez and Gentry were in Baltimore's opening day lineup against Minnesota on Thursday.
Right-hander Alex Cobb was optioned to Double-A Bowie. He is working to get into pitching shape after being signed as a free agent earlier this month.
To make room for the additions, the Orioles designated four pitchers for assignment: Alec Asher, Stefan Crichton, Michael Kelly and Jesus Liranzo.
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