I guess this is old news, but it's the first I've heard of it, so maybe some others are interested...

The Detroit Lions had to scramble to find a quick replacement at both running back and kick returner last week after veteran Justin Jackson unexpectedly retired from the NFL.

https://lionswire.usatoday.com/2023/08/14/justin-jackson-retirement-dan-campbell-explanation-lions-kick-returner/