The thing to weigh up with Rookie you're downgrading to at this stage of the season is do you want them as a cash cow or potential bench cover?
Most are 2 or 3 upgrades away from a completed team, so I would say that the latter is probably more relevant, unless you're well endowed with trades and are looking to use them as cash cow towards a 'Premium' bench type cover.
Now is usually the time where I place particular focus on getting all the pieces of my team in their 'correct' place to ensure that I maximise on any potential DPP status to increase my coverage. As such, the Rookies I select now MUST have a purpose and place for my team. I'm no longer prioritising their potential 'on-field' scores, rather I'm placing more of an emphasis on the flexibility which they will bring for my team.