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Martin Casado, a VMware executive and head of the software-defined networking business unit formerly known as Nicira, is leaving the company to become a general partner at the venture capital firm Andreessen Horowitz. The move was announced today.

Casado is the senior VP and head of VMware’s NSX business unit, the business that’s now on track to do $600 million in annual revenue. The product basically makes communications network more easy to manage and reconfigure using software and with less need to replace hardware.

VMware acquired Nicira, a once-secretive Silicon Valley startup, in 2012, paying $1.26 billion for it. Casado had been a co-founder and chief technology officer. Andreessen led Nicira’s $26 million C-round in 2011 as its first institutional investor.

The move can’t help but be viewed against the backdrop of Dell’s move to acquire EMC, including its controlling 81 percent stake in VMware. VMware shares have declined by 37 percent since the deal was announced last October.

In an interview with Re/code, Casado said the Dell-EMC situation has nothing to do with his decision to leave. “There has literally never been a good time to leave when there wasn’t some larger issue playing out in the backdrop here,” he said. “This time is no different.”

We can certainly take him at his word, but it’s fair to assume that others in his situation might reach a different conclusion. Filings with the U.S. Securities and Exchange Commission show that VMware issued options for 1.1 million shares in exchange for unvested equity in Nicira. On the day the deal closed in August of 2012, VMware shares closed at $92.21.

They’ve been trading below $55 a share since mid-October after the Dell-EMC deal was announced and also as a result of the on-again off-again joint venture with Virtustream. Assuming you’re a Nicira employee whose options were scheduled to vest recently — say, at the end of the 2015 calendar year — you’d have a legitimate reason to be unhappy.