I like Otto Porter a lot. He had a disappointing season offensively last year but has the length and quickness to be a big factor defensively, as well as a pretty good 3 point shot.
But I also like Jeff Green, and god knows the Celtics need his scoring/ability to get to the bucket now more than ever.
I'm a bit torn on this one, but Webster + Porter for Green I'd probabaly pull the trigger on. Washington is allegedly high on Green from what i'ver heard.