Okay, a little time on your hands before the first pitch and you are wondering what one should be doing. Well, there are a few things to do, so lets cut to the chase.
First thing I do is find out how well the players did in Spring Training. The first ratings bump of the season ya know. Well if you don't know, players get ratings advancements every now and then throughout the season and this is the first one. Most generally the young players are the only ones affected, those under the age of 27. But sometimes older players may see an increase or a resettling though rare. Older players may even go down the drain a bit but not usually during Spring Training. Other ratings bumps happen about every 30 games and show progress through playing time.
Now is the time to solidify the rosters, you may want to move players up to fill holes in the minors as they will be ready to play in a couple days. Ahh Hah thought you only needed to worry about the majors huh? If you want to move a player from the minors to the ML roster, you might want to reconsider that for teensy bit. There is this thing about minor league options and ML service time you should read and know about. If a player is not on the 40-man roster his clock hasn't started ticking yet. After three years of ML service time a player can file for arbitration. To stall the arbitration a little, owners wait until the 23rd game of the the minor league season before promoting to the ML level. I usually wait until the player has had his first playing bump.
If I still have some holes to fill in the minors I will check the tryout camp attendees. They may not be all that great but make great fillers. Might want to check out the Free Agent market also, prices will have dropped fanatically.
After all that I usually go to the Management Console and click on Recs at the bottom of the page for each level. This is a quick way to get everything set up and ready to go.
After that it is time to check the ML lineups, two lineups you don't have to worry about right at the moment but depends in which league you are in. Look them over and see if that is how you want them. Normally your best non power hitter with speed is in the first slot. Power hitters usually occupy slots three thru six. I think they still use low eye - high contact over high eye - low contact in the order also if it comes to that. Make sure that Rest, Pinch Hitting and Defensive Replacements are to your liking also. I won't go into great detail about those, just remember if you replace a player or a player goes on the DL at any time those areas need to be updated.
You will need to change the Manager settings to regular season play also. Whether to play areas as Average, Aggressive or other is your choice. Some of them is usually self evident like Base Stealing. If you only have one or two speed guys (remember base running IQ is also involved as well as coaches) then maybe you don't want to go aggressive. But maybe you have a bunch of 60-75 type guys and want to go aggressive on Base Running.
As for the runs and innings, some use 3 and 7th, 3 and 8th, others use 5 and 7th. Basically it depends on the depth of the bench and your personal preferences. If you have better defense on the bench with a lead or maybe a better hitter when behind.
As for Mop Up, I rarely have a guy in this position so I don't use it. I only use my closer in save situations and 9th inning also.
Now for the pitching staff. Check to make sure it is set the way you want, seldom is it the way you envision it or should be for that matter. Then go to the Edit Player Settings section and make sure the pitch counts are the way you want, the call pen setting and the right relief boxes checked. OOps almost forgot about the innings thing in relief. Make sure there is at least one pitcher in relief set to any or 1, as I am sure there will be a starter that can't get past the first inning.
I usually don't look at the minors that much right now. I will run through and check the lineups to make sure the best players are in the right spot in the lineup. Check the pitching staffs and make sure my stars are where they need to be. Remember that players advance with playing time, that means more AB's and innings pitched. But you also can't ignore their stamina and durability. Normally you won't have any problems with that until All_Star break.
After each game you will need to rest pitchers in the pen that have become fatigued. For some reason the Sim will pick on them even though they shouldn't Happens more in the minors that the majors). Normally, if they are not 100%, I rest them til they are. Starters you will need to keep an eye on if they are not recovering from fatigue well enough to make their next start at 100%. Lowering the TPC and MPC will fix that.
I know, some of you have no way of checking after each game and that can become problematic. Having extra pitchers on the Inactive roster helps.