This doesn't pass the smell test. Not only does it not make sense in general, but it couldn't have happened. They could not have traded for Perkins before July 1st, and on July 1st, the lockout was on.
I think it is very believable that Danny has interest in Westbrook, and maybe this deal was brainstormed or thrown out in a conversation as a "what if" once the lockout was over...but this particular deal couldn't have actually been offered in a legitimate sense.
I do think it was the second thing you said with Ainge exploring what he could do early on.
Right, I think it was one of probably 3000 informal discussions he has had since the season ended, and had no more seriousness than any other one.
While I am sure something like this would have been discussed on some level, just like any other move, I think it is a huge stretch to say it was actually "offered". An offer means the team could take it or leave it, and that was impossible here (and we aren't even getting into the fact that Green would have had to be sign and traded).