I think ultimately if he drops the best option at QB for the future would be Trey Lance. I think limited work this year could possibly drop him to the Colts in the 1st round.
Lance is definitely gonna need some time to work on his skills which is why I believe they will bring back Rivers 1 year.
The QB outlook in 21 should be as follows
Philip Rivers 1/20
Trey Lance Starter in 22'
Jacob Eason Backup in 22'