He played all or part of ten seasons in Major League Baseball between 1977 and 1987 for the Houston Astros (1977–78, 1980), Cleveland Indians (1981–85), New York Yankees (1986) and Atlanta Braves (1987), primarily as a backup shortstop and second baseman.

On June 15, 1977, he was traded with Randy Niemann and Dave Bergman for Cliff Johnson.

[1] Fischlin played one game for the Houston Astros' 1980 National League West champion team.

He played from 1977 through 1980 with the Cardenales de Lara and Leones del Caracas of the Venezuelan Winter League.

[2] Fischlin was, along with Bill Caudill, one of the first players represented by agent Scott Boras.