Concurrently, Edgar Gonzalez, who started on Tuesday night and took the loss, will go to the bullpen. Scherzer, making his first Major League appearance, replaced Gonzalez with two outs in the third inning, a runner on second and four runs already in. Scherzer whiffed Astros pitcher Jack Cassel to end the inning and then went on to retire all 13 batters he faced, striking out seven with fastballs that clocked in the mid-90s.
"It was fun, but it was a big relief for me to get my Major League debut out of the way with my family in town and having my girlfriend here," Scherzer said on Wednesday.
Melvin said the decision to move up Scherzer, the team's No. 1 pick and 11th overall in the 2007 First-Year Player Draft, was as much about his potential as it was about the shortcomings of Gonzalez, who goes to the 'pen with a 1-2 record and a 6.55 ERA to show for his five appearances, all starts.
"Obviously, if Edgar had pitched well [on Tuesday], Scherzer never would have been in there," said Melvin, who added that the move was not for the short term, but for at least a finite block of time.
"We do eventually have Doug Davis coming back."
The left-hander, though, is out indefinitely after surgery this month to remove a cancerous thyroid. Davis just began radiation treatment on Tuesday. What that will do to his energy level and stamina at this point is unknown.
Scherzer is a second-year pro with that sizzling fastball. He made four appearances for Triple-A Tucson this season before being called up on emergency relief basis this past Sunday after the D-backs depleted their bullpen in a 13-inning loss at San Diego the previous day. He led the Pacific Coast League with 38 strikeouts and was second with a 1.17 ERA.
There's the probability that Scherzer, 23, has done all he can, preparing to play at the Major League level.
"Mel will make that call," he said. "He was the Manager of the Year in the National League last year. He's a good one, so he'll make those decisions. I'm just going day by day. [Tuesday night] was one outing. I'm not going to sit here and say that I'm ready for the big leagues after one outing. Obviously, it's a long season, and I've got to continue to get better and better."
For now, that long season just got a little shorter with Scherzer at the back end of a rotation that already includes Brandon Webb, Dan Haren, Micah Owings and Randy Johnson, who were a combined 15-2 heading into Johnson's start on Wednesday.