Originally signed as an outfielder, Stieb made rapid progress through the Blue Jays’ system as a pitcher. He finished second on the team in wins (8) in 1979 despite breaking in midway through the season. With an 11-10 record in 1981, Stieb became the first starting pitcher for the expansion Blue Jays with a winning record, and in 1982 he was named TSN AL Pitcher of the Year, with a 17-14 record and a 3.25 ERA. He has also been a very good fielder. Stieb was among league leaders in innings pitched, complete games, and ERA consistently while the Jays were making the transition from an expansion team to a contender. He was outspoken in his frustration about his teammates ‘ capabilities, often asking to be traded. He glowered at teammates who made errors and at umpires whose calls he disliked.
Despite his talent, Stieb has never had an impressive won-lost record (although no Blue Jay pitcher has won more games), and he has shown a tendency to self-destruct late in close games as well as to lose his concentration after temper tantrums. On August 24, 1985, he had a no-hitter through eight innings, then surrendered consecutive home runs to slap-hitters Rudy Law and Bryan Little in the ninth.
Stieb had a team-record streak of 26 scoreless innings in 1985 and led the AL with a 2.48 ERA, the fifth consecutive season he was Blue Jay team leader in ERA. Stieb also led the Blue Jays in innings pitched every season from 1981 through 1985, and led the AL in 1984.
Perhaps chastened by his 7-12 record and 4.74 ERA in 1986, Stieb announced he had become a born-again Christian early in the 1987 season. He regained his form in 1988, posting a 3.04 ERA while going 16-8. Stieb pitched a one-hitter against the Brewers in May, allowing only a single to B.J. Surhoff, and in his last two starts of the season he was one strike away from a no-hitter, only to settle for one-hitters each time. Julio Franco spoiled the first bid with a bad-bounce grounder past the second baseman, and Jim Traber ruined the second with a clean single to right. In his second start of 1989, Stieb one-hit the Yankees, giving him three one-hitters in four starts.