U.S. Senator Thad Cochran takes part in a news conference at the U.S. Embassy in Havana, Cuba, February 22, 2017. REUTERS/Alexandre Meneghini

WASHINGTON (Reuters) - Republican Senator Thad Cochran has delayed his return to Washington following a medical procedure, his office said on Monday, possibly complicating passage of a budget blueprint that is needed to push through the Republicans’ plan for tax reform.

“After a day of monitoring his condition, and on the advice of his physicians and other health care professionals, Senator Cochran has postponed his return to Washington,” said Brad White, chief of staff for the Mississippi legislator.

“The senator has expressed his intention to return to the Senate when his health permits, and to fulfill his commitment and duties to the people of his state,” White said in a statement.

The Senate is trying this week to pass a partisan budget blueprint that would help guide federal spending. Republicans hold a 52-48 majority in the Senate. If Cochran is not present for votes, Republicans could afford to lose no more than one other vote, assuming all 46 Democrats and two independents oppose the budget measure.

In addition to sketching out overall spending levels for this year and beyond, Republicans want to use the “budget resolution” to pave the way for the party later this year or next year to pass a major tax-cut bill without any Democratic support.

Cochran, the chairman of the Senate Appropriations Committee, helps oversee the legislation that funds most government programs and activities. In early December, Congress must extend those funds or risk partial government shutdowns.

(In 4th paragraph, corrects to show that Republicans could afford to lose no more than one other vote, not two votes)