John Costello (baseball)

John Reilly Costello (born December 24, 1960) is a former relief pitcher in Major League Baseball who played for the St. Louis Cardinals (-), Montreal Expos and San Diego Padres. He batted and threw right-handed.

Costello graduated from Oceanside High School in Oceanside, New York in 1979 and then played college baseball at Mercyhurst where he led all of NCAA with a 1.12 earned run average in 1982.

In a four-season career, Costello posted an 11–6 record with a 2.97 earned run average and four saves in 119 games pitched.