Sen. Robert Byrd (D-W.Va.) on Monday looked to tamp down speculation about his political future, with his office saying that he is undergoing physical therapy and anticipating “being released from the hospital— in the near term.

Byrd, 91, has been hospitalized for just more than four weeks after developing what his office initially described as a minor infection. The ailing Senator, the chamber’s longest serving, later developed a staph infection.

Since his hospitalization, Byrd’s office has given few details about his whereabouts, condition and treatment. But on Monday, aides looked to strike a positive tone about his status.

“His spirits are extremely high and he continues to appreciate the well wishes from all, especially the people of West Virginia,— said the statement, which also noted that Byrd is not expected to return to the Senate this week.

Also Monday, a spokeswoman for West Virginia Gov. Joe Manchin (D) denied a story published Sunday in the Charleston (W.Va.) Gazette that noted that the governor spoke with state Democratic Party Chairman Nick Casey and Senate Majority Leader Harry Reid (D-Nev.) last week “to discuss contingencies— in the event Byrd cannot continue his Senate duties.

“There was no conversation in regards to that topic whatsoever,— Manchin spokeswoman Sara Payne told Roll Call, later adding that the governor “did speak with [Reid] recently as he often does, and they speak about various issues.—

“We’re all just praying for Sen. Byrd, and West Virginia needs Sen. Byrd and we hope to see him back at work soon,— Payne said.

Reid spokesman Jim Manley declined Monday to comment on the alleged conversation between his boss and Manchin.

Byrd was hospitalized on May 15. He has been in and out of the hospital several times over the past year.

With Byrd’s absence and the absence of Sen. Edward Kennedy (D-Mass.), who is battling brain cancer, Reid is left without two key members in his Conference. But even with the votes of those two senior lawmakers, Reid would be one vote shy of a filibuster-proof 60-seat majority as the Minnesota Supreme Court weighs a challenge to the recount in the 2008 Senate race between incumbent Republican Norm Coleman and Democrat Al Franken.

Meanwhile, Appropriations Chairman Daniel Inouye (D-Hawaii) will fill in for Byrd by leading a markup scheduled for Wednesday on the fiscal 2010 Homeland Security appropriations bill.

Byrd chaired the Appropriations Committee until last year, when — under pressure from key Democratic Senators concerned about his health — he voluntarily gave up the gavel.

Elected in 1958, Byrd won an unprecedented ninth term in 2006 and is the Senate’s longest-serving Member.