On December 4, 2007 Guillén signed a 3-year, $36 million contract with the Kansas City Royals. His signing moved Mark Teahen to left field, and Billy Butler to first base. He was suspended for the first 15 days of the 2008 season on December 6, 2007 just hours after passing his physical exam. His 15-game suspension was rescinded on April 11, 2008; after the MLB Players' Association and MLB owners agreed on modifications to the current drug testing program. As a result of the agreement, all players implicated in the Mitchell Report were given amnesty.