The veterans that end up on the practice squad will be more of someone transitioning into coaching, not a hidden star.
The old loose salary rules are gone, players on the practice squad are now subject to new pay rules which is fixed at $8,400/week. The exception is players with any number of accrued seasons who are also held to a new set of rules $12,000/week in 2020 and in 2022 it goes to a minimum of $15,400 to a max of $19,900 for this group while all others will receive $11,500/week.
Matt Barkley would be taking a 90% pay cut.