Player availability and cap space will dictate decision making and maybe the threat of competition from other clubs.
SL & NRL teams will be reviewing their squads in prep for the business end of the season so there might be a flurry of players available. Already, we are seeing the lower tier teams in SL in the market to bolster their squads in readiness for the Mid8s, which makes the Carney & Jewitt signings all the more remarkable IMO.
I think the selection of Addy in the half backs last week is suggestive. Sheens has commented he likes strong personalities within the spine, so this might point towards bringing in another half back. Mortimer's name has been circulating for most of the season, and I even heard Scott Prince's name mentioned at Oldham? Although after the Salford game the coaching staff talked about the impact of a player in the mould of Murdoch-Masila?
One thing for sure, Sheens has pulled a number of left-field signings out of his wizard hat, so it will be interesting to see who the next one will be.