Posted by Jeff Zeleny at 6:20 a.m. CDT and updated at 8:55 a.m. CDT

Rep. Lane Evans (D-Ill.), whose battle with Parkinson's disease has kept him away from the Capitol for much of the year, has been replaced as the ranking Democrat on the House Veterans Affairs Committee.

Rep. Bob Filner (D-Calif.), the No. 2 Democrat on the veterans' panel, will succeed Evans.

"The thoughts and prayers of our Caucus are with Lane Evans as his struggle continues," House Democratic Leader Nancy Pelosi said in a statement, adding that Evans' declining health made it impossible for him to continue to perform his duties on the committee.

In March, Evans announced his intention to retire after 12 terms in Congress. The 54-year-old Rock Island Democrat was diagnosed with Parkinson's disease in 1995, but did not reveal his condition for three years, fearful it could be used against him in politics.

As the ranking Democrat on the House Veterans Affairs Committee for the last decade, Evans has been a vigorous advocate for veterans' rights and spearheaded legislation to compensate Vietnam War veterans for exposure to Agent Orange.

Earlier this week, Evans issued a statement calling for an investigation into the theft of personal information from more than 26 million veterans and dependents. The data was stolen from a laptop computer that was taken home by an employee of the Department of Veterans Affairs.

But the theft of the personal information, including Social Security numbers, names and dates of birth, will likely result in Congressional hearings. And Democratic officials said they needed a ranking member to preside over any hearings, so Filner was tapped to temporarily replace Evans, who has been unable to attend committee meetings for months.

"The revelation regarding the theft of sensitive data of 26.5 million veterans and other matters that have arisen require immediate action by the House Committee on Veterans' Affairs," Evans said in a statement Tuesday. "While I am addressing my health matters, I am unable to return immediately to conduct those specific duties."

"I plan to return to work in the very near future," he added. "In the interim, I will be reviewing these issues and working with my colleagues and staff on the Committee to carry out our agenda."