On Thursday, the staff of Disney Animation Studios will gather on the lot for what the company is calling a "Day of Listening," with a handful of human-resources professionals present to facilitate a discussion of workplace concerns.

The gathering, which Disney veterans say is unprecedented for the Burbank-based animation unit, comes as sources with ties to both Disney Animation and Pixar Animation Studios speculate that John Lasseter, who oversees both companies but has been on leave since November, will not return from what was characterized by Disney as a six-month "sabbatical." At the time, Lasseter, 61, acknowledged "painful" conversations and unspecified "missteps" in a memo to staff.

Disney declined to comment, but an insider described the "Day of Listening" as part of a frequent effort to engage with employees.

As The Hollywood Reporter first reported, employees say Lasseter was known — in the words of one insider — for "grabbing, kissing, making comments about physical attributes." Multiple sources say Lasseter would drink heavily at company social events such as premiere parties, but these sources have said the behavior was not always confined to such settings.

While one veteran says he believes the "real reason behind this day of listening is to take the temperature of staff to see how likely it is that Lasseter can come back," he says many in the animation community think Lasseter's return is unlikely. "That's a stretch to put somebody back in charge of animation at such a storied brand as Disney after the revelations of his behavior," he says.

When Pixar had such a listening event several years ago, sources say, employee complaints were aired about Lasseter's behavior generally. When Pixar co-founder Ed Catmull delivered that feedback to Lasseter, one animator says, Lasseter was so angry that he didn't speak to Catmull for more than a week.

Meanwhile, animators have begun to speculate about who would run Pixar and Disney Animation if Lasseter were to not come back. For Pixar, the name most often mentioned is Pete Docter, whose directing credits include Monsters Inc., Up and Inside Out. Docter has for years been a member of the studio's "brain trust" that guides Pixar projects.

But some believe there will not be a single head of animation at either Pixar or Disney Animation and that Docter will be teamed with Finding Dory director and fellow brain trust member Andrew Stanton and possibly another co-head. At Disney, the speculation is that Jennifer Lee (Frozen) and Zootopia co-directors Rich Moore and Byron Howard will form a triumvirate.

Regardless of who is positioned to take over, replacing Lasseter would be a daunting challenge. Since popularizing computer-generated animation with 1995's Toy Story, which Lasseter directed, he steered Pixar to its 2006 purchase by Disney and then revived the fortunes of Disney Animation. Until his sabbatical, he was the most powerful and influential figure in the animation community and a key creative force powering several divisions of the Walt Disney Co.

"Lasseter's precipitous fall caught them all by surprise," says another longtime animator. "They probably assumed it would be a few more years before they needed to think about successors."

In addition, Lasseter had successfully balanced distinct creative environments at Disney and Pixar. "John is also the only creative head who could straddle the separate company cultures of Disney in Burbank and Pixar in the Bay Area," continues the longtime animator. The belief now is that "instead of another capo di capi like him, they would appoint separate leaders."