You gotta love a guy who is taking to the rack like a beast in his first days in camp with the World Champion Celtics, while trying to make the team. Not to mention the kid is humble. 
As the noble poet "Sean Connery" in the good book "Highlander the movie" once pointed out, there can only be ONE (beast) and he's sitting out on the sidelines, most likely trying to strangle Patrick O'Bryant with his eyes for letting TA and the rookies dunk on the first unit, not to mention on his own court
On a more serious note, im reserving judgements for 10 games into the season on Walker, JR and O'Bryant but all three of them are interresting projects to follow.
I doubt Walker will be the steal of the draft when we look back after next season ends but 3 years down the line, if he stays injury free this year the chances of that happening are very big