According to Wagner's LinkedIn page, he is launching a battery and powertrain startup in California. The timeline of his departure is not known.
Wagner, who joined the company in January 2013, was involved in developing technology for all of Tesla's cars, as well as the Powerwall, according to his profile.
Last week, Tesla pushed back its target for volume production on its new Model 3 sedan by about three months, saying it was difficult to predict how long it would take to fix production bottlenecks.
Tesla had also said that the main constraint was its battery module assembly line at its Nevada Gigafactory, where the company had to redesign part of the production process.
Tesla and Wagner did not respond to requests for comment.
Reporting by Aishwarya Venugopal.