Toronto's closer has yet to pitch this season and made only three appearances during the spring, so it's almost like he has to start over and gradually build up his strength and endurance.
"He's so far removed from Spring Training, he didn't have much of a Spring Training anyways," Blue Jays manager John Gibbons said. "I don't see him back here in the next couple of weeks, to be honest with you."
Janssen's injury was originally described by the organization as soreness in his lower back/abdominal muscle. Gibbons clarified Friday that it's an oblique issue, and that type of injury always has the danger of lingering for an extended period.
That's one reason Janssen's recovery has taken longer than first anticipated. The Jays hoped he would be ready by the middle of April, but when he began a rehab assignment earlier in the month, the soreness had yet to go away and he was shut down after just one appearance.
"It wasn't like a setback, but there's still something there that's holding him back a little bit," Gibbons said. "Psychologically, he doesn't feel quite ready to cut loose because something is just nagging at him right there in his oblique."
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.