Elon Musk is almost irreplaceable as Tesla CEO, analysts and investors told Business Insider. But if he did leave, these contenders could replace him.

Matthew LaBrot, a Tesla employee who created the website Tesla Employees Against Elon Musk, was fired from the company two weeks ago. LaBrot claimed in a LinkedIn post that he was terminated for having created the site, and because he was part of a larger group of employees who publicly asked Elon Musk to resign from the company.

Matthew LaBrot railed against the CEO on a website he created called Tesla Employees Against Elon. A Tesla employee says he was fired after publicly blaming the company’s cratering sales on CEO Elon Musk and his political activities.