Put the players on the DL when their team announces it. You're waiting several hours which can effect the abilities to move lineups around.
I am not sure how your software works to recognize when a player is placed on the DL, but teams are announcing players on the DL several hours prior to Yahoo actually designating the players as DL eligible. This can cause issues for a manager that is trying to get max value of their roster.
Mark Brunette commented
How do we find the official time the player is placed on the DL? Following transaction was done on Aug 19th - Blue Jays place Marcus Stroman on 10-day dL retroactive to Thursday Aug 16. Recall LHP Thomas Pannone from Buffalo. Purchase the contract of RHP Justin Shafer. option LHP Luis Santos was optioned to Buffalo.- Shafer and Pannone both pitch in game on Aug 19th, Marcus Stroman does not get DL eligibility until 12:42 am on Aug 20th more than 8 hrs after the game has concluded. Stroman was clearly placed on the DL before the game because neither Shafer or Pannone would have been eligible to pitch, but the DL did not come into affect until almost 12 hrs later.
Yahoo waits for the player to be placed on the MLB DL officially before assigning them DL status.
A report by a team that a player is going on the DL is not enough, it has to be officially completed.