General manager Alex Anthopoulos was pressed for details on the injury and Happ's future role on the team during a Wednesday evening scrum with the reporters.
"We'll deal with all of that," Anthopoulos said. "Look, hopefully, like anything, we have five starters that are rolling and they're winning all of their games and we have too many starters. That would be a great problem to have. I would sign up for that right now.
"But you deal with those things as they come. Every day something else could happen, in the next 10 days, two weeks, you can't plan that far ahead."
Happ dealt with a sore back early in camp but eventually returned to the mound with several weeks remaining and was adamant that everything was fine. That tone continued through his final outing of the year but quickly changed when the Blue Jays announced their 25-man roster on March 26.
There had been some speculation that Happ would be headed for a role in the bullpen, but instead the club announced his back was still an issue and placed him on the DL. Anthopoulos stressed that there was still a spot for the seven-year veteran in the rotation.
Toronto started the year with R.A. Dickey, Drew Hutchison, Mark Buehrle, Brandon Morrow and Dustin McGowan in the rotation. It would likely take one of those starters to either falter or get injured for Happ to get another chance. Anthopoulos remained vague about that, though, and said that's not something the club will seriously consider until Happ eventually goes through a rehab assignment in the Minor Leagues.
"If we all of a sudden have six starters that are performing great, I don't think we're going to go to a six-man rotation; we would deal with that then," Anthopoulos said. "We expect J.A. to be a part of the rotation and we expect that when he's healthy to be a really good performer for us."
But there's no guarantee that Happ will have a spot?
"No, certainly, the same way there's no guarantee with every single starter over time, things can happen, performances, things like that," Anthopoulos said.
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.