Seems like Pistons aren't getting back much from Bojan but he's 34 and has 2 years left on his contract. Getting an expiring contract where you can cancel his team option this off-season, you will get 2 seconds for this upcoming draft. Since you are already off to one of the worst seasons ever you might as well blow it up. For the Pistons if you decline Fournier's option you will have nearly 60 million in cap this offseason hoping to sign someone big.
FA Targets for Pistons this upcoming offseason (*=Declined option/RFA):
Pascal Siakam
Nicolas Claxton
Kelly Oubre Jr.
De'Anthony Melton
OG Anunoby*
Immanuel Quickley*
For the Knicks you get rid of someone who has played one game all season and helps off-load the shooting guard position. Adding Bojan will allow DiVincenzo to come off the bench leading to a deadly start 5 and 5 coming off the bench.
Knicks Rotation (Healthy): PG: Brunson, Quickley SG: Barrett, Hart, Grimes SF: Bogdanovic, DiVincenzo PF: Julius Randle, Gibson C: Robinson, Hartenstein