Setting: Top Prospect List: Dynamic
The game seems to look for the last time the player was ranked in the top 100, regardless of time:
Example #1:
Mann 'is' the #14 prospect according this news article from September 2021, but that was actually back in 2020, he was 3rd in the Rookie of the Year Award since then
Example #2, different savegame:
Trade that happened July 22nd, 2014
Khris Davis got as note: #38 prospect, but that was one year ago.