The veteran right-hander is scheduled to rejoin the Blue Jays in Toronto on Monday. He'll continue receiving treatment and will eventually transition to bullpen sessions before going on another rehab assignment.
"He'll have to start that all over again," Blue Jays manager John Gibbons said. "He didn't really have much of a Spring Training anyways. ... He hasn't thrown a lot in the last couple of months. I would hope not longer, but I would expect at least two weeks."
Janssen has yet to pitch this season after suffering the injury during an exhibition game in Montreal late in the spring. He previously missed approximately a month of Spring Training because of a sore right shoulder.
Right-hander Sergio Santos will continue to receive most of the save opportunities during Janssen's absence, while left-hander Brett Cecil also remains a possibility as well depending on matchups.
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.