Joseph Andrew Thatcher (born October 4, 1981) is an American college baseball coach and former professional baseball pitcher. He played in Major League Baseball (MLB) for the San Diego Padres, Arizona Diamondbacks, Los Angeles Angels of Anaheim, and Houston Astros.

Thatcher was a member of Kokomo High School's baseball and basketball teams for four years; he was an all-region basketball player. He was a freshman on the 1997 team that played in Indiana's final true state tournament and set a school record for 3-pointers in a game as a senior in 2000.

Thatcher pitched for four seasons with Indiana State University. In 2003, he played collegiate summer baseball with the Bourne Braves of the Cape Cod Baseball League. He served as the Sycamores' closer in 2004, his final year with the team.

Thatcher was not drafted upon graduating college, he signed with the River City Rascals of the independent Frontier League, appearing in 47 games (6-5 W/L, 10 Saves) in 2004 and 2005.

Thatcher was signed by the Milwaukee Brewers as a free agent in 2005 and assigned to the Rookie League Helena Brewers.

Thatcher had progressed to the Triple-A Nashville Sounds in 2007 when he was traded to the San Diego Padres, along with prospects Will Inman and Steve Garrison, for relief pitcher Scott Linebrink. Thatcher was immediately placed in the bullpen of the Padres big league club.

Thatcher made his Major League debut with the Padres on July 26, 2007, in Houston against the Astros. He appeared in 22 games in 2007, finishing with a 2–2 record and 1.29 ERA. He also appeared in 8 games with the Triple-A Portland Beavers.

Thatcher began 2008 with the San Diego Padres, but was sent down to Portland in mid-May after posting a 6.75 ERA in 16 appearances. He made nine more appearances with the big league club in 2008, the final one on July 23. He finished the year with a 0–4 record and 8.42 ERA in San Diego. With Portland, he posted a 2.77 ERA over 39 total innings.