The Hawks do have a choice, they could have signed him to their active roster when the 9ers came sniffing around. They decided not to.
I was wrong, they did have a choice.
Source says 49ers are in talks to sign WR Chris Harper of Seahawks practice squad, but Seahawks are trying to hold onto him. Nothing signed.
The San Francisco 49ers signing of Seahawks practice squad wide receiver Chris Harper appears to be just about official at this point. The team has not announced it, but after Adam Schefter reported it this morning, Matt Maiocco has his own source confirming the deal is done. The deal was held up as the Seahawks reportedly were trying to retain Harper.