Mejia is opening the year with High-A Lynchburg, MLB.com reports.
It was initially reported that he had been optioned to Double-A out of big-league camp this spring, but he will instead head to High-A after spending most of 2018 at Low-A. Mejia was a low-key breakout prospect last year, getting his fastball up into the mid-90s while flashing a couple plus breaking pitches. If the 6-foot-4 righty carries over last year's success to High-A and possibly Double-A later this season, he could shoot up prospect lists.