And if wants to buy into that role there can be minutes for him
That's the money quote right there. If Giddens wants playing time, he has to accept that he's not getting a lot of shots on a team with Paul Pierce and Ray Allen and KG and 'Sheed and House and BBD and.........
This quote, here, makes everything that happened last year make sense. When Walker was on the floor, what did we see? Not really a great player, but someone who was hustling, exerting effort on D, not taking a lot of bad shots, etc.
I'm convinced that at least so far, Walker has been the guy who has understood what the coaches are looking for from him (to be a high-energy, defensive-minded role player), whereas this transition away from being The Man has been a lot more difficult for Giddens.
So, Walker gets to dress, Giddens does not. Walker gets a little playing time, Giddens plays eight minutes all season. Walker stays with the parent club, Giddens gets humbled by being sent to the D-League.