He played in Major League Baseball (MLB) for the Houston Astros, Chicago Cubs, and Cincinnati Reds.

[2][3] The Houston Astros selected Buchanan in the eighth round of the 2010 Major League Baseball Draft.

Pitching to a 3.80 earned run average, the Astros named Buchanan their Minor League Pitcher of the Year.

[4] Assigned to Corpus Christi to start the 2013 season, Buchanan led the Texas League in ERA and walks plus hits per innings pitched during the first half of the season, and the Astros promoted him to Oklahoma City after he participated in the Texas League All-Star Game.

The Cubs eventually won the 2016 World Series, giving Buchanan his first championship title, although he did not play in the postseason.

[15] He did not play a game for the team because of the cancellation of the ALPB season due to the COVID-19 pandemic and became a free agent after the year.

On March 2, 2021, Buchanan signed with the Gastonia Honey Hunters of the Atlantic League of Professional Baseball.

[17] He made 16 appearances (6 starts) for the Triple-A Salt Lake Bees, registering a 3–4 record and 7.12 ERA with 39 strikeouts in 43.0 innings pitched.