Despite Happ's lack of work, Toronto will now hand the ball to him for Game 1 of its series against the Phillies. It was originally scheduled to be a spot start, but after Brandon Morrow tore a tendon in his right hand, Happ now has an opportunity to enter the rotation on a more permanent basis.
"It's a little bit of a concern, but what are you going to do?" Happ said of going almost two weeks without pitching in a game. "I think when I go out there I'm going to try and forget about that and just focus on trying to execute. I can't really change the reality of that, that is what it is. I'll do my best."
Happ tried to prepare for his start by throwing a side session during Friday night's game in Pittsburgh. He waited until the ninth inning to get warmed up because there was some uncertainty about whether he would be needed for an inning or two out of the 'pen.
It's a less-than-ideal situation, but Happ will need to make the most of it if he wants to remain a starter. Prospect Marcus Stroman was promoted from Triple-A Buffalo on Sunday morning, and he will most likely take a starting spot away from either Happ or right-hander Dustin McGowan.
"Really the only thing that I can do is throw when I feel like the opportunity is there," Happ said. "Before that side [Friday night] I threw two other ones after it had been a few days without throwing. That's really all you can do, [Friday] night ramp the intensity up to make it as similar as possible."
Happ entered Spring Training with a supposed guaranteed job in the rotation, but his prolonged struggles combined with a sore back to cost him the opportunity. Happ instead began the year on the disabled list and eventually joined the bullpen when he was activated on April 15.
The 31-year-old made 18 starts for the Blue Jays last season and posted a 4.56 ERA. He has a career record of 40-42 with a 4.24 ERA in 137 games, which includes 114 starts.
"Right now I feel strong," Happ said. "I'm going to be as honest with them as I can, and we'll just take it as it goes. I don't know an exact pitch count; we'll just have to see."
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.