I wish it could be like this every night! Walker really deserves to play more. 
Deserves? I'm not sure how much more he can play. He picked up five fouls in very limited minutes. He's still a rookie warts and all. He gave us quality minutes against one of the worst teams in the NBA, let us not go crazy.
Sure, he was in trouble because of his fouls but I loved his energy and I think he can bring some assets to the bench's offense (he seems to have a good jumpshot and he sure can drive to the lane). But you're right he played well against the Grizzlies, one of the worst teams in the league. Still, during the absence of T.A, Scalabrine, etc, I think it will not cost much to the team to give Walker more minutes! To improve he'll have to play more anyway and if he keeps giving quality minutes (who knows?) he could allow Pierce to get some additionnal (and much needed) rest.