Crow made his first major league appearance on March 31, 2011, which was Opening Day. He faced four Angels batters, striking out three.
On May 30, 2011, Royals manager Ned Yost announced that Crow had been promoted to the team's closer position on a temporary basis to replace the struggling Joakim Soria. However, on June 6, Yost announced that Soria had earned the spot back. Crow had no save opportunities in his brief stint as closer.
In 2011, Crow was selected to the All-Star Game, although he did not play.