At the same time, they won't be re-signing Bulaga, so he'll be moving on. I understand the logic - he's looking at a big contract, and with his injury history it may be more prudent to let some other team take that gamble.
I have mixed feelings about the Kirksey signing, but the way his contract is written, it's basically a win-win for the Packers. That said, they need a serious upgrade at the position, so I wouldn't be surprised to see them still use a high pick there.