Does keeping a player from playing allow him to recover more quickly?
If you play an injured player, can he get a second injury?
Is he more likely to get injured again?

Any other helpful tidbits on injuries?

Any info/help is appreciated.

Injuries have different grades; other than out, you can still select them in overrides or depth chart, but if playing, the injury level will affect their performance.

there's a fair bit of info scattered around.

https://www.myfootballnow.com/community/search?search=injuries

Going purely on memory, so I could be wrong.
1. Physical interactions with other players can cause an injury.
2. Playing sitting active or inactive does not affect healing.
3. Current injuries will increase the chances of getting another. As long as 1 is met.
4. The injured body part does lower the ratings of the affected body part. A zero will lower a rating up to 25%
5. Multiple injuries to an area will compound the effectiveness to one rating. Like leg + ankle both affect max speed.
6. Conditioning/fatigue regulate injuries.
7. Multiple Injuries affect retirement.
8. Interactions with larger players causes more injuries.

Thanks for the input, I appreciate it.