Escobar, who did not miss a game last season, was struck in the face by Danny Salazar's pitch in the fifth inning Wednesday night in Cleveland.
''He took his impact tests and there were some issues with it in terms of reaction speed and stuff like that,'' Royals manager Ned Yost said. ''This is something you don't fool with. I've seen end guys end their careers with concussions.''
The Royals recalled infielder Orlando Calixte from Triple-A Omaha. He was hitting .167 with one home run in 12 games.