Think I've just cobbled together the knowledge from reading about Lions scrubs over the years. Plus I had a friend who was a cousin of
Josh Ferguson, he came to our church one week and we took him out to do Street Teams (homeless outreach), afterwards we went out to dinner. He gave me a lot of insight into how flimsy contracts are and some of the economics of being a fringe player in the NFL.
There are around 2300 NFL players under contract. The 53-man active rosters + 16-man practice squads is 2208 (69 x 32.) Plus around 88 players currently IR-R (players designated to return.) Plus another subset who were put on IR and won't return or took an injury settlement and were released.
Out of all those players, there are 112 players with fully guaranteed contracts. Minimum salary is $750,000 for rookies, and it increases with each accrued season: Y2 $870K, Y3 $940K, Y4 $1.01M, Y5-Y7 $1.08M, Y8+ $1.165M For practice squad, rookies get $12,000 per week, or $216,000 for an 18 week season. Veterans on the practice squad get $16,100 or $289,900 for a full season.
Players are vested in the Player Annuity Program after 3 credited seasons. That's a big deal because you get health insurance for life and are eligible to take money out of your account as soon as five years have passed since the last Credited Season. You are eligible to take installment payments or monthly lifetime annuity payments once you are age 35 and at least five years have passed since your last Credited Season.
Seasons accrue when you are on the roster, IR or PUP for 6 games. However, NFI and practice squad players do not accrue seasons; that's only if you are on the 53-man.