WASHINGTON (REUTERS) - President Donald Trump is considering nominating Federal Reserve Governor Jerome Powell and Stanford University economist John Taylor for the central bank's top two jobs, in an apparent bid to reassure markets and appease conservatives hungry for change.

Under that scenario, either Powell or Taylor would take the reins from Fed Chair Janet Yellen early next year, with the other filling the vice-chair position left vacant when Stanley Fischer retired this month.

"That is something that is under consideration, but he hasn't ruled out a number of options. He'll have an announcement on that soon, in the coming days," White House spokeswoman Sarah Sanders told reporters on Friday.

Making Powell, a soft-spoken centrist who has supported Yellen's gradual approach to raising interest rates, the next Fed chief would provide the continuity in monetary policy that investors crave.

The addition of Taylor, who has backed an overhaul of the Fed and embraced a more rigid rule-oriented monetary policy, would be a feather in the cap of conservative Republicans who feel that Fed policy has been too loose under Yellen.

"I think Powell might be the safer pick insofar as we know what we're getting," said Michael Feroli, chief US economist at JP Morgan Chase. "He's a guy who obviously knows the Fed culture, how the (policy-setting) committee operates, so for some of those soft skills we know he would be effective."

Powell has embraced the Yellen Fed's monetary policy, keeping the faith that a tighter job market will eventually push wages higher and end a lengthy period of worryingly low inflation.

Taylor has spent the last two decades refining and advocating wider use of a rule that lays out where rates ought to be, given certain conditions of inflation and the broader economy. His rule implies they should be higher than they are.

'SCOPE FOR DISAPPOINTMENT'

Although Taylor is highly regarded within the Fed, his rule-based rate-setting position has spurred criticism that he would handcuff US monetary policy.

The academic pushed back at a meeting at the Boston Fed on Saturday, saying he favored a flexible implementation of policy rules and did not want to tie the Fed's hands or suggest that he was motivated by a distrust of policymakers.

"I think that's completely incorrect," he said. "I trust policymakers; (rules) are an effort to make policy better."

Some analysts suggest that fears that Taylor would bring an inflexible monetary policy with him to Fed, as some Republicans in Congress hope, are likely exaggerated.

"There is some scope for disappointment if people think putting Taylor in will just lead to mechanical-based policy," Feroli said.

Cleveland Fed President Loretta Mester, speaking with reporters on Friday, seemed to agree.

"Even if you pick a rule, the rule itself would need to be modified given the structure of the economy," she said.

"But I do think being systematic, looking at the kinds of information we look at systematically over time, articulating our strategy for policy and being less discretionary is a good idea."

At the same time, there are concerns that the combination of Powell and Taylor atop the world's most powerful central bank could send a confusing signal to markets.

It is unclear whether Trump, who has criticized Yellen's stewardship but also said on several occasions that he preferred rates to stay low, wants to dramatically alter the Fed's direction.

Although he appears to be tilting to Powell and Taylor, the Republican president has also interviewed Yellen, his top economic adviser Gary Cohn and former Fed Governor Kevin Warsh for the Fed chief position.