That bond fund, which had been managed by Gross since 1987, has had about $10 billion in outflows since the announcement on Friday of Gross's surprise jump to Janus Capital Group (JNS) .
"We do not believe that these changes of Bill Gross's departure causes an imminent risk of significant outflows from the fund," said Morningstar's Michael Herbst, director of manager research for active strategies in North America.
As of Friday, the fund had $221 billion in assets under management.
Herbst said that Pimco's Total Return Fund owns highly liquid fixed-income assets, meaning that only a sustained rise in outflows would cause the performance of Gross's Total Return Fund to suffer, potentially affecting broader fixed-income markets.
Morningstar has withdrawn its ratings on the Total Return Fund as it weighs the impact of Gross's departure and Pimco's appointment of Mark Kiesel, Mihir Worah and Scott Mather to manage the fund.
"We are very familiar and very comfortable with these three managers," Morningstar's Herbst said of the promotions. Kiesel was Morningstar's manager of the year in 2012. Worah is an expert in real estate and Mather an expert in global bond allocation.
Sweeping change at Pimco
On Friday evening, Pimco made a series of promotions and new assignments in an effort to respond quickly to Gross's departure and restore investor confidence in the nearly $2 trillion investment management firm.
Daniel Ivascyn, a long-time top manager at Pimco, was appointed the firm's group chief investment officer, while five other portfolio managers were given CIO roles.
The firm elected Andrew Balls, Virginie Maisonneuve, Kiesel, Mather and Worah as CIOs. Worah will also work with Balls to manage Pimco's trading floors globally. Ivascyn will work with portfolio managers Saumil Parikh and Mohsen Fahmi to manage Pimco's Unconstrained Bond Fund.
"The management and investment structure put in place in January as well as the thorough succession planning gives us complete confidence in PIMCO's investment and executive leadership team," Allianz CEO Michael Diekmann said in a statement.
Germany's Allianz owns 70 percent of Pimco after acquiring a majority stake in the asset manager for $3.3 billion in 2000.
Todd Rosenbluth, director of exchange-traded fund and mutual-fund research at S&P Capital IQ, noted in a Friday interview that top managers such as Ivascyn and Worah have shown strong performance in recent years, often topping Gross's returns with their funds. Nonetheless, Rosenbluth believes Gross's departure will cause some Pimco fund investors to move their money elsewhere.
Total outflows expected to be higher
The Wall Street Journal reported that Pimco is preparing internally for about $100 billion of aggregate outflows because of Gross's departure. Separately, Vincent Lui, a Morningstar stock analyst covering insurers said, "it is likely that tens of billions, if not hundreds of billions in AUM, will follow Gross to Janus from Allianz."
Were those amounts of outflows to be spread across Pimco's total portfolio, it could prove manageable given the size of the asset manager.
Gross's Total Return Fund had significant outflows even before his exit. In September, the fund reported its 16th consecutive month of outflows, putting total redemptions above $60 billion during that period.
Pimco spokesman Michael Reid didn't respond to an email seeking comment.
More from TheStreet: