Kristian Campbell quickly fell into lockstep with the Boston Red Sox and the big leagues after his debut. He fell out of it just as fast.
After a stellar first few weeks in the big leagues, Campbell had already signed a contract extension with Boston, batted .301/.407/.495 and netted American League Rookie of the Month honors for April. Then, he suddenly looked lost at the plate, and was demoted back to Triple-A by mid-June.
Jen McCaffrey of The Athletic interviewed Red Sox director of player development Brian Abraham about Campbell's rookie year, which he admitted did not go according to plan (subscription required).