I'll start right off by saying these are not big issues. If they persist, I won't quit the game or anything. But if you're planning on building a team focused on defense, they are things you should probably be aware of that I've run into over the last few seasons:
1) The DH exemption to the Rest depth chart
When HBD was designed, it was apparently designed with offense, and not defense, in mind. As a result, if you have a player in as your starting DH who has any other positions listed on his player card, and the starter at that other position gets Auto-Rested, the game engine will plug your DH in at that position - regardless of where, or even if, the DH is listed on your Rest depth chart.
Example: I've got a couple of guys who were drafted as catchers but who really are just DHs with mediocre AS, AA and PC ratings. I had them listed as DH/C, figuring they might have to play behind the plate in an extra-inning game or something if my bench got depleted.
Later in the season my starting catcher fell below his Rest %. Rather than give my backup catcher (the #2 guy on the Rest chart) the start, Sparky decided to move my starting DH (one of those guys drafted as a C) in at catcher, and put someone else in at DH.
When I sent in a ticket about it, I was told "This is special case logic in the game to prevent the manager from wasting players and giving them the best bat in the game."
No, I don't know what 'wasting players' was supposed to mean either. But the bottom line is, when the engine makes decisions on its own, it only thinks about offense. And it will completely disregard your depth charts when doing so.
2) There's no emergency bad enough to use a Resting player
In a recent game, my starting CF fell below his Rest%. I have five players listed on the Rest/Defensive Replacement charts at CF. The #2 guy went in at CF. The #3 guy went in at LF with that player Auto-Resting as well. The #4 guy was starting at SS. #5 guy, the other half of my SS platoon, was on the bench.
The game went to the bottom of the 9th - I was at home and losing. One of the ex-catcher DHs was used as a pinch-hitter for the CF. This turned out to be a good move, and he was a big part of a rally, eventually coming around to tie the game.
At this point, Sparky decided to use my other SS - the last guy I had listed on my CF depth chart - to pinch-run for the guy who'd driven in the tying run, who happened to be my other SS. The rally died, the inning ended, and for the top of the 10th my #2 SS stayed in at short... while my crappy-fielding DH/ex-C stayed in center field.
The number of things wrong with the scenario are legion. Why wasn't the backup SS used to pinch-run for the slow-footed DH who represented the tying run, at which point he could have stayed in CF? Why was he used as a pinch-runner at all, if he was the last guy on the bench on my CF depth chart after the CF had been removed from the game?
Most baffling though, why didn't my resting #1 CF come into the game after all that to replace the DH?
When I sent in a ticket, I got told "Players below their auto rest will almost never come into a game and only do in emergency situations when it's absolutely necessary." How having a DH who's a bad defensive catcher play CF doesn't count as an "emergency situation" and "absolutely necessary", i have no idea, but again it's clear the engine gives no thought or priority to defense at all.
In both case, I got told something like this as a 'solution':
"To prevent this, you would need to lower the players' auto rest settings and adjust your lineups so they aren't starting. Then they would be available to come into games."
In short: if you plan on building a team around defense, be prepared to do a metric crapload of micro-managing. Because the engine is going to try and sabotage your defense if you give it a chance.
Thank you for your time, and God bless the United States of America.