As front offices bring in new acquisitions, they simultaneously must evaluate their overall rosters, trim exorbitant contracts and work out trade deals for starters who may not fit into their long-term plans.
The first wave of free agency typically prompts secondary roster transactions. In some cases, it's best to recoup cap savings on a contract, especially when there's no dead money owed on the remainder of said deal. An abundance of talent at a position also allows teams to shop certain players on the trade market.
General managers will continue to fill voids during the 2018 NFL draft in April, which makes ineffective players expendable.