Phil Knight and other parts of the Nike universe lauded the hiring of Elliott Hill as the sneaker giant’s next chief executive officer, but good vibes alone won’t be enough to fix a company in turmoil.

The hedge fund billionaire Bill Ackman has bet big on the iconic American brand. His firm, Pershing Square, acquired three million shares, or 0.2 percent, of Nike this spring. His stake is currently worth about $250 million.

The athletic giant announced Thursday that CEO John Donahoe will retire next month and will be replaced by Elliott Hill, a veteran former Nike executive. Nike’s stock rose 9% during after-hours trading Thursday,