Peter Thomas Harnisch (born September 23, 1966) is an American former Major League Baseball right-handed pitcher.

He played in Major League Baseball from 1988 through 2001 for the Baltimore Orioles, Houston Astros, New York Mets, Milwaukee Brewers and Cincinnati Reds.

Harnisch studied accounting, and was a star pitcher at Fordham University, compiling a 21–3 college record, 2.29 earned run average and 213 strikeouts in 204 innings pitched.

In a transaction considered by Orioles fans as the worst in team history according to Thom Loverro,[2] Harnisch was traded along with Steve Finley and Curt Schilling to the Houston Astros for Glenn Davis on January 10, 1991.

A torn tendon in his pitching arm caused Harnisch to miss the entire month of June 1994, and limited him to just 17 starts all season.

Hina prescribed sleeping pills for Harnisch prior to his opening day start for the Mets against the San Diego Padres.

Harnisch made three starts and one relief appearance for Milwaukee, and signed with the Cincinnati Reds as a free agent following the season.

He enjoyed something of a renaissance with the Reds in 1998, going 14–7 with a 3.14 ERA for a team that went 77–85 and finished in fourth place in the National League Central.

[17] Harnisch was inducted into the Suffolk Sports Hall of Fame on Long Island, New York, in the Baseball Category with the Class of 2009.