He only wore it for his 2005 rookie season so he became 23 in 2006
it's customary for most teams to assign rookies with higher numbers (or left over numbers) and then if they look like they will be come a constant starter they normally get a lower number after a year or two..
occasionally a real high profile rookie will get a low number straight off the bat.
really just depends how a team feels, and often they like to give a lower number a year off if it was just held by a "club champion"
Roughhead was drafted ahead of buddy in that draft and he only got 35!