The popular vendor of lamb, and lamb sandwiches has left Union Market saying the market no longer fits the model that first attracted Border Springs. They announced the move recently on Twitter, but this Washington Post piece gives a little more context, and explains the reasons for the move. They aren't going far. They will do production work at Union Kitchen, but it doesn't sound like they will sell anything out of there directly.
Interestingly, the main issue seems to be that they first agreed to be part of Union Market (they were always technically in pop up, not permanent, status) with the understanding that it would be more of a food market where they could sell butchered lamb, and sausages for customers to cook at home. But over time, they say it became more of a high end food court, and they found themselves selling way more sandwiches than meats. Edens (the owners of Union Market) seemed to take a little umbrage at the whole "food court" assertion as you can see in the tweet below (Tim Carman, author of the Washington Post article characterizes their response).
Edens responds to @BorderSprings' departure from @UnionMarketDC. They say calling it a 'food court' misses the point. http://t.co/if0MIbPWOjHow do you view Union Market? Does it differ from the original idea as you understood it? What direction would you like to see the market take, and do you think that direction would be economically feasible?
— Tim Carman (@timcarman) August 15, 2013