According to the Wall Street Journal, the endorsement letter does not mention Larry Summers, who has also been floated as a possibility. One Democratic senator who signed the letter voiced his apprehension to the paper.
"There's a lot of concern among a lot of Democrats about an appointment of Larry Summers to that long-term position as Fed chairman," said Sen. Tom Harkin (D-Iowa). "He was one of the architects of getting rid of Glass-Steagall, of getting rid of other regulations."
Speculation has surfaced that Yellen would be a front-runner for the position, with Washington Post columnist Neil Irwin citing her as "unquestionably qualified" due to her economic worldview and high-ranking experience.
Harkin and his colleagues in the letter are not alone in their concern, as some activists have also favored Yellen over Summers.
"It is high time to shatter the glass ceiling at the Fed and appoint a woman to a post that impacts so many women, and Janet Yellen would be a much celebrated pick," Shaunna Thomas, co-founder of feminist group UltraViolet said, according to a Tuesday HuffPost report.