When a trade involves a “Player to be named later,” it means that the teams involved have agreed to include an additional player in the trade at a later date. This player is typically agreed upon by the teams within a specified period of time, often within six months. This allows the teams to complete the trade without finalizing the specific player at the time of the initial trade. It is often used when the teams need more time to assess potential players or when they want to include a player who is currently ineligible to be traded.
I was asked about this by one of my managers. I researched and yes, it can be done. It is not considered collusion provided it is announced up front and is a fair trade.