On April 29, 2008, Scherzer made his MLB debut against the Houston Astros when he came on in relief and threw 4 1⁄3 perfect innings while striking out seven. While doing so he also set the record for the number of consecutive batters retired (13) for a pitcher making his MLB debut as a reliever. The previous record was 12 set in 1962 by the Dodgers Pete Richert. The seven strikeouts were one short of the major-league record for most in a debut relief appearance. The Pirates Barry Jones had eight on April 20, 1986. On April 30, 2008, the Diamondbacks announced he would be placed into the starting rotation, due to his impressive debut. In his first appearance as a starter for the D-Backs, Scherzer allowed five runs (two earned) in four innings, while striking out five, taking the first loss of his major league career. He returned to the bullpen for much of the 2008 season. He started against the Cardinals on September 24 and lost for the fourth time in his career in a winless season, going five innings, allowing seven hits and four runs (two earned) while walking two and striking out four.