The only reason that I can see for only putting 38 on the main list and beefing up the rookie numbers is that it is part of the overall strategy for fitting in contracts for Cotchin, Riewoldt and Martin in 2014.
By leaving two places vacant, this may bring their Total Payments for 2013 to below 95% of the Salary Cap. In turn, this may allow them to pre-pay other players during 2013, freeing up Salary Cap space for the following year. It may also leave scope for the three players to receive a “signing-on” fee of some sort, which can be accommodated under this year’s salary cap.
We will know more next week but it looks like the rookie list will have a combination of younger players (Darrou, Verrier and probably one or two more) who most likely won’t play much in 2013 and a couple of older players who will only get a game if a run of injuries hits. Either way, they are all likely to be on pretty basic wages, unless injury really hits.