And just to add to the already solid answer, in order to maintain game shape try to get guys 48-75 minutes per week. If you're a bit under or over once in a while it should average out but don't play guys 85-120 minutes a week. Barring an injury it's really inexcusable to have a guy with anything below respectable game shape in the middle of the season, with the possible exception of the week after the all star break. After week 2 most of your guys should have strong or proficient game shape. Also, stamina is very important but if it gets too high (strong-proficient-prominent) then it might hurt your rotation as those guys will not often come out of games. Aim for mediocre-respectable stamina if possible.
I wish there were pigmen. You get a few of these pigmen walking around I'm looking a whole lot better. Then if somebody wants to fix me up at least they could say, Hey he's no pig-man!