Per this note by @chrishah, I made a manual override for players the system might think are retired but aren’t. Miles Mikolas in this example has been playing in Japan for 3 years, and by not playing in a baseball game in the minors or majors in 3 years, the system thought he was retired.
If there are other players that you can’t find in search but you know are still active, perhaps playing in Korea or Japan and eyeing an American return, please let me know!