I'm able to do it, but only for the Tigers, and it is complicated. You can use transaction logs, but they are sometimes incomplete and don't necessarily let you know if the transaction happened before or after the game. Then you get the <20 day rule, grievances, the September 1 rule, the 3-days after Labor Day rule, etc.
It's nice that places like BP, FG, and Cots report it to the January number so you don't have to unbake their assumptions.
The guy on twitter I found this year (Lee calls him Pirates Edman) is trying it for every player, importing transactions daily. I want to tackle that if I can trust the transactions log, and am in the process of transitioning my sheet from Google to Excel to maybe up the scraping capability.