Hayden Field is The Verge’s senior AI reporter. An AI beat reporter for more than five years, her work has also appeared in CNBC, MIT Technology Review, Wired UK, and other outlets. Five months after returning to OpenAI, Barret Zoph — the company’s head of enterprise AI sales — has departed, The Verge has learned. Zoph returned to OpenAI in mid-January after a stint as co-founder and CTO of Thinking Machines Lab, the competing AI company founded by former OpenAI CTO Mira Murati. Shortly after Zoph returned to OpenAI, the company said he would lead its push into enterprise — a significant role at OpenAI, since in recent months it had vowed to stop chasing so-called “side quests” and focus on key revenue drivers like enterprise and coding ahead of its planned IPO. OpenAI confirmed to The Verge that Zoph will be departing. He posted a goodbye message in the company’s Slack channels. Zoph did not immediately respond to a request for comment. Are you a current or former OpenAI employee?…