I would guess the team adds a starting caliber bat. Someone who is a better hitter than Bellinger but not necessarily a better player. In my mind's eye this is Tyler O'Neill, but don't get too hung up on him specifically. But it looks something like this
- Yankees take Bellinger and his contract for a nominal return
- Cubs sign Tyler O'Neill for 2-3 years and $15-18M per. He is now the starting right fielder
- In addition to backfilling Bellinger, you have A) saved $7-10M outright and (IMO) B) eliminated the need for a Patrick Wisdom backfill on the bench
The Cubs now have $35-40M to spend under the cap, and the to-do list is: additional SP, late inning reliever, reserve IFer (ideally LHH), and backup catcher. That is a bit tight if you do all your shopping in FA, but pretty easy if you stack even one more trade on.