An All-American in ice hockey at the University of Vermont, McCaskill was runner-up for the Hobey Baker award (college hockey’s player of the year) in 1981 and played professional hockey for the Sherbrooke Jets (American Hockey League) in 1983-84. He began to concentrate on baseball full-time in the summer of 1984 and was promoted to the Angels in 1985, finishing 12-12 in his rookie season.
McCaskill blossomed in 1986, with a 17-10 record, 202 strikeouts, and a 3.36 ERA for the AL West champion Angels, but he lost Games Two and Six to the Red Sox in the LCS. He missed most of 1987 after surgery to remove bone chips from his pitching elbow and was only 8-6 in 1988, but in 1989 McCaskill reestablished himself as one of the AL’s top pitchers as the resurgent staff of the Angels carried them to contention.
California chose not to re-sign him after he posted a 10-19 record in 1991, only the second losing season of his career. After signing with the White Sox in December 1991, he spent only one more year as a full-time starter before being moved into a setup role.