Microsoft would not confirm the report, although SGI told The Wall Street Journal he was leaving to take a "non-CEO" position at another company.

Belluzzo was hired 19 months ago from Hewlett-Packard Co. to help the company expand its product line. SGI was planning to launch a new line of computers that would use Intel Corp. microprocessors and Microsoft Corp. software. However, that decision was in effect reversed on Aug. 10 when SGI announced a restructuring and plans to lay off up to 17 percent of its 9,000-member work force.

Belluzzo is expected to begin his new position around Sept. 1.

The appointment comes as Microsoft is considering to issue a tracking stock that would follow the value of its Internet holdings. Although sources told the Journal those plans have been temporarily shelved, Microsoft may be considering a spin-off or sale of some of its Internet operations.