An adviser and speechwriter to Sen. Bernie Sanders Bernie SandersTrump, Biden will not shake hands at first debate due to COVID-19 Sanders tells Maher 'there will be a number of plans' to remove Trump if he loses Sirota reacts to report of harassment, doxing by Harris supporters MORE (I-Vt.) said Thursday that the White House hopeful is starting to be taken more seriously as a top-tier candidate in the crowded 2020 Democratic field.

David Sirota told Hill.TV that “folks are starting to notice that Bernie Sanders has a real shot" at becoming the Democratic presidential nominee.

“I want to be clear: We have known that Bernie Sanders has a real shot to win this nomination and to defeat Donald Trump Donald John TrumpBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Pelosi: Trump Supreme Court pick 'threatens' Affordable Care Act MORE," Sirota said.

Sirota argued that the perception of Sanders among voters has a lot to do with the national media's coverage of the senator. Sanders and his allies have long complained about what they see as unfair coverage, claiming that his campaign is often cast in a negative light.

“The revelation ... among the political class is ‘wow, Bernie Sanders really does have a serious and significant and real shot to win the nomination and win the presidency,’ ” he said.

Sanders continues to be among the top four candidates nationally, according to several polls.

A Reuters-Ipsos poll released last Friday showed Sanders in second place with 14 percent support behind former Vice President Joe Biden Joe BidenBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Joe Biden should enact critical government reforms if he wins MORE with 19 percent. Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) trailed with 9 percent, Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE (D) had 6 percent, and former New York City Mayor Michael Bloomberg Michael BloombergBloomberg rolls out M ad buy to boost Biden in Florida Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Bloomberg pays fines for 32,000 felons in Florida so they can vote MORE, who made his debut in the poll, registered 4 percent support.

Biden has 28.5 percent in the RealClearPolitics average of recent national polling, while Sanders has 17.8 percent, Warren has 15.3 percent, Buttigieg has 9 percent and Bloomberg rounds out the top five at 5.5 percent support.

—Tess Bonn