Tesla’s milestone on Monday in a single week, a long sought goal for the automaker, is being dimmed by the departure of another executive. Doug Field, Tesla’s top vehicle engineer, is leaving the company for good, after stepping away for a reported leave of absence in May.

Tesla confirmed the departure in a statement to Jalopnik, after the Wall Street Journal .

“After almost five years at Tesla, Doug Field is moving on,” a Tesla spokesperson said in a statement. “We’d like to thank Doug for his hard work over the years and for everything he has done for Tesla.”

Tesla poached Field from Apple in 2013, when he moved from to leading Tesla’s vehicle programs. In May, he stepped away from work at Tesla for what a spokesperson described as “time off” so Field could “recharge and spend time with his family.”

The Wall Street Journal said the time off was supposed to last six weeks, but he hasn’t returned. It’s unclear why he decided to leave permanently, but follows the departure of several high-level executives over the past two years as Tesla has struggled to ramp up production of the Model 3 sedan.

CEO Elon Musk in April that he’d sidelined Field and took over his position as the exec with “direct control of the division producing vehicles.”

Musk said he’d asked Field to manage “both engineering & production,” but as of now, it’s “better to divide & conquer.”

Weeks later, Field went on temporary leave. Now, he’s out for good.

A Tesla spokesperson reached out to clarify that Field was NOT the top engineer at Tesla, but rather that he was the top vehicle engineer. Much as there can only be one God, there can only be one Top Engineer at Tesla, who is Elon Musk. Second engineer at Tesla is JB Straubel. - M.B.