In candid interviews with The Hollywood Reporter, the cast and crew and other insiders revealed that Miller often acted unprofessionally.
"There are a lot of different ways you can find out somebody doesn't want to do the show anymore," creator Mike Judge said.
Some of those ways, one unnamed source explained, were showing up to table reads late and unprepared, falling asleep between takes, and unpredictable behavior and performances on a day-to-day basis.
"These guys are the Golden State Warriors of comedy," said co-showrunner Alec Berg said. "So, it's like, yeah, we've lost Andre Iguodala but we still have Steph Curry and Kevin Durant and Klay Thompson and some other guy on the Warriors whose name I don't know. But I don't feel like we can't win championships anymore because we've lost ..."
Berg paused and then added, "T.J. wasn't LeBron."
"Silicon Valley" returns for a fifth season March 25 on HBO.
For his part, Miller said he would fall asleep on set because he was doing stand-up comedy at night.
"So, the thing I have a problem with? It's pushing myself to do too much," he said.
As for the Lebron comment, Miller found it hilarious. "Oh, that's great," he told THR. "And it makes me like him more [because] he's so good at being an a--hole."