The Arizona Diamondbacks' top prospect, outfielder Ryan Waldschmidt, is officially set to make his major league debut. Waldschmidt, Arizona 's No. 1 prospect and MLB Pipeline 's No. 49 overall prospect for 2026, has been promoted to the big leagues, the Diamondbacks announced on Friday. To make room for the 23-year-old on the active MLB roster, Arizona designated outfielder Alek Thomas for assignment. So far in 2026, Waldschmidt is hitting .289 with three home runs, 22 RBIs, and six stolen bases in 34 Triple-A games. After a somewhat slow start at the plate with the Reno Aces, the 2024 first-round draft pick had his breakout performance at Triple-A on April 9 when he went 4-for-5 and finished a double shy of a cycle. And now, Arizona is giving its top prospect the chance to showcase his talents in the big leagues.…