YES!!! Excellent pick-up, if they sign him for the money they have available.
I've wanted Pryz for a few years. Tough, tenacious, and even a little mean, he's a terrific rebounder and simply a huge body to throw out there.
Injury-risk? Yeah, but we all discussed this on the site already (few weeks back on a Leon Powe thread). With a veteran team like the Celts, who are over the cap and have limited funds available, there are three player options: scrubs, ring chasers, and injury-risks.
Scrubs aren't worth it. Ring chasers would rather go to Miami or Chicago. We're left with injury-risks.
If Pryz is brought on as the 15th guy and he stays healthy, this would be an ABSOLUTE STEAL. If he gets injured, the team is no worse off. They can always cut him and go brag Stiemsma again.