I don't think Vassell has been that bad at all. Dude's shown consistent grit getting deflections and fighting for rebounds. During the first half, he was pretty much the only guy doing that. In the second half, other players started helping, and it made all the difference. While it would have been ideal if he'd stepped up as the second option with Wemby out, this was a game where the other guards combined for 78 of the team's 120 points. I'm not mad that he was able to find his impact elsewhere.
Keldon not stepping up is more concerning, because he can break defenses when he's scoring well. Portland has good size on the wings, and I think that's making them a bad match-up for him. Johnson is the fourth piece of the driving puzzle along with the point guards. The team misses Johnson's vertical pressure more than it misses Vassell scoring 20 points.