The lanky McWilliams won his first seven big league decisions, including August 1, 1978, when his surprising catch helped stop Pete Rose‘s 44-game hitting streak. Following arm trouble, his delivery was revamped by coach Johnny Sain from a slow motion to an accelerated, whip-like delivery. McWilliams peaked as TSN NL All-Star lefthanded pitcher for 1983. He was fifth in the Cy Young voting and had more strikeouts (199) than any Pittsburgh pitcher since 1969. He was relegated to relief and spot-start duty after further arm trouble in 1985.
