Word of his possible departure has been rumored since the May layoffs, but an EA representative reportedly confirmed to GamersGlobal that Zeschuk "outlined his plan to return to his family in Edmonton for a much deserved vacation." The site also suggested that Zeschuk has been absent from the studio for several weeks, and there were fears within the Austin studio that both Zeschuk and co-founder Ray Muzyka were planning to leave.
The rep went on to clarify: "Greg also announced the new GM of BioWare Austin and Old Republic, Matt Bromberg. Greg is still with EA. He's now back in Canada, taking time off and thinking about new projects. No change with Ray Muzyka."
As this is still a rumor at this point, we must note that official confirmation from EA hasn't been made on this report. We will update with any news as it's made available.
[Update: Gamasutra reports that Zeschuk is not leaving BioWare completely; he did leave his General Manager role back in May.]