I don't blame the team for this - the blame is squarely on Washington's shoulders. I don't understand why players HAVE to smoke weed all the time... and there's plenty of players I know that do it, so I really wonder how much worse it has to be for you to get tagged for it.
I doubt the Cards picked up the option having any clue that he was going to get a one-year suspension for drug use.
They probably should have tested him the day before picking up the option just to see if he was clean. Stupid rule anyway. In no way does it affect his performance on the field.