He played all or parts of 11 seasons in Major League Baseball, from 1977 to 1987, for the San Diego Padres, St. Louis Cardinals, Cincinnati Reds, New York Yankees and Kansas City Royals.

Shirley was originally drafted out of Putnam City High School in 1972 by the Los Angeles Dodgers, but chose to attend the University of Oklahoma.

Shirley skipped several levels of minor league baseball, being assigned directly to the Double-A Amarillo Gold Sox to start the 1976 season.

He posted what turned out to be one of his best seasons in his rookie year, setting what would be career highs in wins (12), games started (35), innings pitched (214) and strikeouts (146).

Although he pitched occasionally in relief, he remained in the rotation until July, when he was moved to the bullpen after a start in which he gave up six runs on seven hits and five walks in six innings.

After spending one season in St. Louis, he was traded during spring training 1982 to the Reds for a pair of prospects, one of whom was reliever Jeff Lahti.