Malinga has been troubled by a niggling knee problem which has kept him out of Sri Lanka"s ongoing tour of West Indies.
The 24-year-old was signed by Mumbai Indians at the IPL players" auction in February but has now revealed he may not be fit in time for the start of the tournament.
"I've had this injury in Australia and played with it," Malinga explained. "However as it got worse I couldn"t tour the West Indies too. I would have loved to be with the team and enjoy its success. I am still under treatment and working hard," he added.
"It is tough at this stage to be sure about IPL, but I am very hopeful I can make it."
Mumbai Indians open their IPL campaign against Bangalore Royal Challengers on April 20.