Longtime Tesla executive JB Straubel is leaving his post as chief technology officer after some 15 years, CEO Elon Musk announced Wednesday evening. Straubel will transition to a “senior advisor” role, according to Musk, and is not fully leaving the company. The news comes as Tesla announced a $408 million loss for the second quarter of 2019.

“I’m not disappearing, and I just wanted to make sure that people understand that this was not some, you know, lack of confidence in the company, or the team, or anything like that,” Straubel said on the call.

“I’d like to thank JB for his fundamental role in creating and enabling Tesla,” CEO Elon Musk said on a call with analysts Wednesday evening. “If we hadn’t had lunch in 2003, Tesla wouldn’t wouldn’t exist, basically.”

Vice president of technology Drew Baglino will take over Straubel’s responsibilities, Musk said, though it’s unclear if he’s formally assuming the CTO role. “I’ll just say, you know, obviously, big, big shoes to fill,” Baglino said on the call.

Straubel joined Tesla in the mid-2000s, right around when Musk first invested in the startup, which was founded by Martin Eberhard and Marc Tarpenning. He and Musk retroactively refer to themselves as co-founders

Straubel is the second C-suite executive to announce a change in his role on one of Tesla’s earnings calls in the last six months. Longtime chief financial officer Deepak Ahuja announced he was retiring on a call in January. Tesla also has a well-documented revolving door when it comes to lower-level executives.