Apple (AAPL) - Get Report CEO Steve Jobs, whose health has been of major concern to the company's investors, underwent a liver transplant about two months ago, according to a published media report.

The Apple co-founder, who has been on medical leave since January, had the transplant in Tennessee and is expected to return to work as scheduled later this month, although he may begin with a part-time schedule, said the report, which

The Wall Street Journal

published Saturday on its Web site.

When Jobs went on leave, he didn't disclose his specific health condition, although he is a pancreatic cancer survivor.

Jobs didn't respond to an email request for comment, the

Journal

reported. The newspaper quoted an Apple spokeswoman saying, "Steve continues to look forward to returning at the end of June, and there's nothing further to say."

Jobs, who in the 1990s returned to the company he had founded, is credited as the mastermind behind Apple's resurgence. Investors have worried for some time about his health, fearing that there is no successor capable of filling his shoes should he die or have to leave the company permanently.

Apple shares closed Friday at $139.48, up $3.60 or 2.65%.

This article was written by a staff member of TheStreet.com.