2/8/2019; updated 2/14/19
OOTP will not allow a sim to run when there are teams in violation of the roster limits. The option Ask A.I. to set up complete team, lineups, etc. will send players down and/or bring players up so that the Active Roster is full. It is also very likely to change the team's pitching assignments, starting lineups, and depth charts. It will not, however, release players if the team is over the limit, so if I am being prevented from simming because a team or teams have too many players on their Reserve Rosters, I will Ask A.I. and then release the oldest players on the Reserve Roster until every team is compliant with the roster rules. So if you don't want the A.I. or me messing with your team, make sure you're not violating the roster limits!
These are the roster limits:
Spring Training sims
Some people like to put all their best players on their Reserve Roster during Spring Training to protect them from injury. You can do that, but remember you're limited to 15 players on the Reserve Roster. Don't go over that limit, or I'll have to Ask A.I.
Opening Day sim
Do not forget to export for the Opening Day sim. Make sure you have the league file that has the same game date as Opening Day, and make sure you haven't accidentally left too many players on your Active Rosters, because if you have, I'll have to Ask A.I., and all that work you did will be wiped out.
Roster maintenance during the season
You're a better GM/manager than the A.I. is, or at least you are when you're paying attention to your team. If you're missing export after export, you're worse than the A.I. would be. The A.I. makes some goofy decisions but it doesn't do things like not replacing an injured pitcher in the starting rotation, or letting a player take up a roster spot for three weeks instead putting him on the 60-day DL when he's going to be out for 13 months. I'll probably Ask A.I. for any team that's missed three or more exports in a row, unless the GM has communicated with me and provided roster instructions.
Free Agent signings during the season
When you offer a free agent a contract he may sign in the middle of a sim. If the signing puts you over the roster limit the sim will stop and I will have to resolve the roster violation by releasing a player. If youíre offering contracts while your roster is full, itís a good idea to message me beforehand and tell me who you want me to release in the event a player signs with you mid-sim. Otherwise Iíll have to make the decision for you.