Sen. Lamar Alexander (R-Tenn.) said on Monday that he opposes Judy Shelton's nomination to the Federal Reserve board, but he won't be in Washington this week to vote against her.

“I oppose the nomination of Judy Shelton because I am not convinced that she supports the independence of the Federal Reserve Board as much as I believe the Board of Governors should. I don’t want to turn over management of the money supply to a Congress and a President who can’t balance the federal budget," Alexander said in a statement.

Alexander, who is retiring at the end of his term, is the third GOP senator to oppose Shelton. GOP Sens. Susan Collins (Maine) and Mitt Romney (Utah) have also said they will vote against her.

But a spokesman for Alexander noted that he will be out of Washington, D.C., this week due to family matters, meaning he won't be in the Senate chamber to cast his vote.

Alexander's opposition comes after Senate Majority Leader Mitch McConnell (R-Ky.) teed up a vote on Shelton's long-stalled nomination for this week. That vote is expected to take place Wednesday.

With Sen. Lisa Murkowski (R-Alaska) announcing on Thursday that she would support Shelton's nomination, Trump's Federal Reserve pick appeared to be on a path to confirmation after being stuck in limbo for months. 

Shelton’s nomination faced fierce headwinds amid bipartisan opposition over her previous support for returning to the gold standard and using inflation as a tool to make U.S. exports more competitive.

Even as McConnell decided to move forward on her nomination, she has a razor-thin margin for getting confirmed with Republicans holding a 53-47 majority.

In addition to Alexander's absence, Sen. Rick Scott (R-Fla.) announced over the weekend that he would quarantine after being exposed to someone who tested positive for the coronavirus. Vice President-elect Kamala Harris also routinely misses Senate floor votes. A spokesperson didn't immediately respond to a request for comment on Monday about if she would return to Washington to vote against Shelton. 

If Alexander, Scott and Harris are absent, and everyone else votes, that would put Shelton's confirmation at 49-48, just over the simple majority required. If Harris returned to vote against Shelton's nomination, Vice President Pence could still break a 49-49 tie.