WASHINGTON — Rep. Jesse Jackson Jr., though released Tuesday from the Mayo Clinic, skipped a well-attended gathering of House Democrats Wednesday, while a colleague speculated that Jackson may not return to Congress during the ongoing lame-duck session.

Jackson, 47, who has bipolar disorder, missed the first votes of the lame-duck session Tuesday. The Illinois Democrat has been on medical leave since June, and reportedly is under federal investigation for alleged misuse of campaign funds.

The Mayo Clinic, which revealed Tuesday that Jackson had left the hospital, issued a statement Wednesday indicating Jackson remains under medical care “to manage and treat depression.”

The statement read: “Congressman Jesse Jackson Jr. is no longer a patient at Mayo Clinic. He departed Tuesday, Nov. 13. Although he is no longer a current patient, he continues to cope with bipolar II disorder and will remain under the care of physicians as part of his ongoing treatment to manage and treat depression. He and his family remain grateful for support and prayers offered and received on his behalf.”

Rep. Mike Quigley, D-Ill., said Wednesday he isn’t anticipating seeing the ailing lawmaker during the remaining weeks Congress will meet this year.

Quigley, a former defense lawyer, said he had little direct knowledge of Jackson’s situation, but his months-long absence suggested he would sit out the remaining weeks Congress is in session.

“I don’t anticipate him coming back,” he said. “It’s just at this point, you assume he’s not coming back if he hasn’t come back [since June].”

At Wednesday’s Democratic caucus gathering in a packed room, lawmakers welcomed Democratic members-elect and heard Minority Leader Nancy Pelosi’s aim to retain the post.

Jackson never came up in public remarks, Quigley said.

Talking about Jackson’s absence as Congress is poised to make major decisions on budget cuts and taxes, Quigley added: “I’m not sure the votes on the fiscal cliff will be close, but every vote matters. We’re members of Congress. I think every vote matters.”

Jackson entered Congress in 1995 and won another two-year term on Nov. 6.

Frank Watkins, Jackson’s press secretary, had no comment on the congressman’s whereabouts or plans.