UPDATED 05/03/12 1:32 p.m.

CHICAGO (CBS) — Nearly four months after suffering a stroke, U.S. Sen. Mark Kirk (R-Ill.) has been released from the Rehabilitation Institute of Chicago and is now back at his Highland Park home.

Kirk’s family announced Thursday that he had been released from the rehabilitation center in Streeterville.

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Kirk will go on working on his recovery as an outpatient at the Rehabilitation Institute. He is working on a walking study program to improve his mobility while maintaining his schedule with staff, his family said in a statement.

“We are grateful for the wonderful doctors and personnel at the RIC for their care of Mark, and to the residents of Illinois who have given him privacy and time to heal. We also thank everyone who has shared their prayers and wishes for his return to the U.S. Senate as soon as possible,” the statement said.

Kirk’s family expressed gratitude for the doctors at the Rehabilitation Institute, and everyone who has shared prayers for Kirk to return to the Senate floor as soon as possible

Kirk suffered the stroke in mid-January and he underwent surgery at Northwestern Memorial Hospital. He had been undergoing intensive physical therapy at the Rehabilitation Institute since mid-February.

U.S. Rep. John Shimkus (R-Ill.) met with Kirk in March. At the time, The Chicago Sun-Times quoted Shimkus as saying that mentally, Kirk is sharp, and already would be capable of casting “knowledgeable votes” in the Senate.

Doctors have said Kirk should make a full mental recovery, though they expect him to have limited movement on his left side.

Physicians have said Kirk suffered an ischemic stroke, the most common type. According to the American Stroke Association’s website, ischemic strokes account for about 87 percent of all cases. They are the result of an obstruction within a blood vessel that supplies blood to the brain, caused by fatty deposits in the blood vessels.

Kirk, a North Shore Republican, was elected to the U.S. Senate in 2010, winning the seat once held by President Barack Obama. Before that, he spent 10 years in the U.S. House.