According to the New York Times, Ricardel had accused some of Trump's most trusted aides of inappropriate behavior which the first lady said were false claims.
Bolton brought Ricardel on board in May to serve as his No. 2 on the National Security Council.
Aides said Ricardel clashed with the first lady's staff over her visit to Africa last month. Sanders did not elaborate on what Ricardel's new job would be.
"I usually have so many words - I have the best words", she said, quoting President Trump.
Ricardel was sacked Wednesday evening following a rare public rebuke from the first lady's office.
"It is the position of the office of the first lady that [Ricardel] no longer deserves the honor of serving in this White House", the first lady's communications director, Stephanie Grisham, said in a statement.
CNN reported Wednesday morning that it's still not clear if Ricardel has actually been dismissed, and cited a White House insider saying that neither President Trump, his chief of staff John Kelly or press secretary Sarah Huckabee Sanders knew that Melania would be releasing the statement condemnin Ricardel.
Government Backflips, extends My Health Record Opt out period until January 31st
Labor's health spokeswoman Catherine King said the government had quietly capitulated in the Senate to the extension. If the date wasn't shifted, millions of Australians would have automatically joined the scheme.
In a highly unusual move on Tuesday, Melania Trump's office called publicly for the ouster of a senior member of her husband's staff earlier this week.
Trump said in an interview Wednesday with The Daily Caller that 'I will be making a decision on homeland shortly.
Ricardel also had a fraught relationship with Kelly and Fuentes, according to people familiar with the matter.
As her post as deputy national security adviser, Ricardel was number two to John Bolton and sat in a number of briefings alongside the president.
She's regarded as inflexible and obsessed with process, which some officials complain has complicated co-ordination between the NSC and cabinet agencies. Ricardel was the third person to hold the post under Trump.
Another expected reshuffle casualty is Homeland Security Secretary Kirstjen Nielsen, a Kelly ally who oversees the politically sensitive task of carrying out Trump's crackdown on illegal immigration.
Nick Ayers, a 36-year-old chief of staff to Vice President Mike Pence and renowned political consultant, is reportedly high on Trump's list as a replacement.