Jim Calhoun underwent a two hour surgical procedure to remove a large extruded disk fragment that was pressing on the spinal nerve and decompressed the area around the nerve.

"Everything looks encouraging," said George Blaney, who has been filling in for Calhoun since Feb. 3. "Pat [Calhoun, Jim's wife] called and said the doctors were really pleased with what went on in the procedure."

Calhoun had been diagnosed with spinal stenosis, a narrowing of the spine, normally associated with aging and sometimes with arthritis.

There is no timetable for Calhoun’s return.