The Royals immediately put Buck in their starting lineup, replacing injured veteran Benito Santiago.

Although he initially appeared overmatched by major-league pitching—his batting average reached a low of .138 on July 7—he impressed the team with his defensive ability and his handling of pitchers.

[4] On December 16, 2009, Buck signed a one-year contract with the Toronto Blue Jays worth $2 million.

Buck was elected to the 2010 American League All-Star team on July 4, along with fellow Blue Jays Vernon Wells and José Bautista.

[8] In his first game with the Marlins, he hit a grand slam off New York Mets pitcher Mike Pelfrey.

[12] On November 19, 2012, Buck was traded to the Toronto Blue Jays along with Josh Johnson, José Reyes, Mark Buehrle, and Emilio Bonifacio, in exchange for Jeff Mathis, Adeiny Hechavarria, Henderson Álvarez, Yunel Escobar, Jake Marisnick, Anthony DeSclafani, and Justin Nicolino.

[13] On December 17, 2012, the Blue Jays traded him, Noah Syndergaard, Travis d'Arnaud, and Wuilmer Becerra to the New York Mets for R. A. Dickey, Josh Thole, and Mike Nickeas.

On August 17, Buck was placed on paternity leave, and he was replaced on the roster by the catcher he was traded with, Travis d'Arnaud.

[21] The Angels designated Buck for assignment on October 7, 2014, after claiming Alfredo Marte and Roger Kieschnick on waivers.

[28] In December 2011, Buck assisted in rescuing two elderly women from an overturned car in Sunrise, Florida.