[Timofmars]

Maybe make Andrew Miller the left specialist as primary role, middle reliever as secondary. Either way, he probably would get used as middle reliever only if everyone else is tired (though maybe he gets used a bit if he hasn't been used in a while?). But with being the only lefty specialist primary would maybe make him get used more often in that situation, helping the other lefty to be fresher. That may make him less likely to be "forced" into the ML role due to being the only rested one, and then having to face righties.

You can also set Miller's strategy to be pulled very early, so the AI may be more likely to pull him out when he faces a righty. You can check his L/R split stats after some games to see if it's working (see if he is facing only lefties), or check game logs to see if he was pulled when a righty came up.

Mike Morin might not have many opportunities to be used in high leverage situations since he will be getting used probably any time he's rested, but the high leverage setting won't hurt. Assuming that the AI tries to select the best rated player available when all else is equal, you could maybe set a few more guys to high leverage just to have the chance to be used in those situations when not tired, to replace a weaker pitcher that may be pitching at that time. I think if no rested pitcher is set to high leverage and rested, the AI will just stick with the current pitcher.