Pandora (P) shares were gaining on Friday morning after the company extended the deadline for investors to propose board changes at the internet radio operator, a sign Pandora may be forced to replace directors or key executives.

Extending the deadline to nominate alternative board members to March 17 from Friday comes as Corvex Management, the hedge fund controlled by Keith Meister, a Carl Icahn protege, increased its total stake in Pandora to 10% amid calls that the company be sold. CEO Tim Westergren, a co-founder who returned to the company a year ago, is under increasing pressure to sell the company, which has seen its stock fall more than 65% over the past three years.

Shares on Friday were up 3.5% to $12.87. 

Among those clamoring for a sale is BTIG media analyst Rich Greenfield, who said in an investor note published on Thursday that Pandora has made a string of questionable strategy decisions and then compounded its problems by management missteps.

"Pandora's management team has executed poorly for far too long, with significant executive churn and shifts in strategy," said Greenfield, who rated the share neutral. "Investors are no longer willing to give management yet another chance."

That "executive churn" is a reference to a number of management changes including the abrupt resignation in December of Pandora's former chief operating officer, Sara Clemens, who had only been in the position since March 2016, and the company's decision to announce in November that Mike Herring would give up his role as finance chief but then not actually replace him until earlier this week, with the hiring of Naveen Chopra

A Pandora official declined to comment on the BTIG report.

Greenfield hinted that Pandora may be hit in the coming weeks with a proxy fight, asserting that "we believe it is highly likely that ... Westergren will lose his board seat at the upcoming annual meeting." Pandora's board is elected on a staggered schedule, and only Westergren and independent member Tony Vinciquerra are up for election this spring.

For Pandora, much is riding on its ability to successful launch and grow an on-demand subscription service that will directly compete with industry leader Spotify as well as Apple Music (AAPL - Get Report) , Amazon (AMZN - Get Report) , Alphabet's (GOOGL - Get Report) YouTube and Jay Z's Tidal. The platform, Pandora Premium, has been a central focus of the company for more than two years. It's expected to go live sometime this month.

Nonetheless, Greenfield argued that getting into a market already dominated by much larger corporations was "foolhardy," he said. Spotify is the market leader with 40 million monthly subscribers to its on-demand service.

Rather than bolstering the company's finances, Pandora Premium risks becoming a drain on the company's already sensitive balance sheet, Greenfield said, citing minimum guarantee revenue deals with music labels that could end up being higher than the rates set by the U.S. Copyright Royalty Board. 

Its best alternative, he said, is putting the company up for sale -- exactly what investors have been anticipating for more than a year.

In recent weeks, Pandora's shares have spiked or sunk on comments from executives at Liberty Media (LMCA) , majority owner of Sirius XM Holdings (SIRI - Get Report) , the satellite radio operator that has built a healthy business in new cars. The general thinking is that Liberty could benefit from Pandora's free radio technology, which provides listeners with music based on their individual preferences.

But earlier this week, Liberty CEO Greg Maffei, who is also chairman of Sirius XM, said that Pandora's shares were overvalued, charging that it's "not clear the valuation makes sense." Maffei has often sent mixed messages about Pandora, balancing his appreciation for its free radio service -- but not its decision to get into the on-demand market -- with comments that its executives have failed to execute. 

As for an acquisition of Pandora, Maffei said that would be "interesting" but only at "the right price." On those comments, Pandora's shares fell 6% on Tuesday.

If Pandora's board does decide to sell, it probably would only do so if it could get more than $16 per share, the IPO price. But with Sirius XM the only apparent (semi)-interested party, Pandora seems unlikely to find itself at the center of a bidding war. If that's the case, Greenfield recommended that Sirius XM should offer to buy the company at its current stock price, arguing that the shares already are trading at a premium based on buyout speculation.

Sirius XM couldn't be immediately reached for comment. Meanwhile, Pandora shares were off 0.4% Thursday afternoon to $12.48.

How should you play markets in March? Here's what Jim Cramer and four of our top columnists recommend.