Matthew Allen Peacock (born February 27, 1994) is an American professional baseball pitcher who is a free agent.

He has previously played in Major League Baseball (MLB) for the Arizona Diamondbacks and the Kansas City Royals.

Peacock underwent surgery on his throwing arm in 2016, and he did not make an appearance that season, instead choosing to work at his uncle's sawmill.

[6] Following the season, Peacock was selected by the Arizona Diamondbacks in the 23rd round of the 2017 Major League Baseball draft.

In 2018, Peacock began the season with the Kane County Cougars (with whom he was named a Midwest League All-Star)[9] before being promoted to the Visalia Rawhide.

[12] On April 6, 2021, Peacock was promoted to the major leagues for the first time to fill in for the injured Joakim Soria.

[18] Peacock spent brief time in the Royals’ minor league system, appearing in games for the Double-A Northwest Arkansas Naturals and the Triple-A Omaha Storm Chasers.