I'm noticing a lot of exhaustion injuries going around. Even though it's computer, you need to monitor your players minutes! Each player/team will behave differently depending on many factors. One thing is to watch your guys minutes played.
Some guys can handle more than others. Check the players condition and if it's dropping, check the minutes played and aim to reduce it as a starting point. Maybe your guy is taking too many hits and you might have to find a way to hide him from it. A lot of information is spit out after each game to help you gauge where you guys are playing and there are lots of options in the client to balance the load.
Goalies is all about shots, higher the shots, the more tired they get. If you're getting tons of shots agains, like me, then you need to figure out who's the sieve on D, or maybe you don't have the right forward pairings. Check +/- stats to see which combinations are letting you down.
Autolines won't do any of this thinking for you and will often overload your star player. Just some things to keep in mind.
Anthony