I got 2 solutions here but its really unrealistic (like this is not gonna happen in real life), and this will change your team a lot. I cant seem to find a solution without trading other player first.
Solution 1:
P.J.Brown+Snyder->Marvin Williams(Atlanta)
Speedy Claxton->Kwame Brown(Laker)
Marvin Williams->Gerald Green+Scalabrine(Boston)
Kwame+George Lynch+Rasual Butler->Swift+Norris+Vin Baker
Solution 2:
P.J.Brown+Snyder->Marvin Williams(Atlanta)
Speedy Claxton->Kwame Brown(Laker)
Marvin Williams+Kwame Brown->Paul Pierce+Gerald Green(Boston)
Paul Pierce+Lampe+Vroman->Swift+Weatherspoon+Juwan Howard
I dunno why some trades can be made (Another EA glitch maybe). I think Lakers want the trade because their lack of PointGuard, and for Boston im not sure. It is said that Marvin Williams+Kwame Browncan be traded for Paul Pierce+Ricky Davis. If im playing the dynasty, i might choose solution 1 and stick with Kwame and Green. But i think ill choose solution 2 and stick with Paul Pierce lol
Also some funny thing when I was solving this. When i was simulating the season waiting for the response from Atlanta (Marvin Williams)(Lakers response "Speedy" lol), i received a mail from Boston asking to trade Vroman for Gary Payton LOL
