Ynoa was called up from Triple-A Gwinnett on Saturday.
The 21-year-old owns an unimpressive 4.87 ERA split across the three highest levels of the minors this season. His 11.0 percent walk rate is poor, though his 26.2 percent strikeout rate is fairly strong. Dan Winkler was optioned to Triple-A Gwinnett in a corresponding move.