Initial rankings mean very little. I had a great starting team last year - was ranked 30th after 3 rounds and stayed in the top 200 for the first half of the season. Saved up enough trades for the second half, then bang, backline crisis. I end up running out of trades [NB - I didn't literally run out of trades, but I was so busy dealing with the likes of Cornes, Drummond, PBurgs, Symes, that I had few upgrade trades) and wearing 1 zero each week for the second half of the season. Team slides down into 1000th place.
There will always be injuries. Your team will almost never be at 100%. The best teams are those which are happy to stay at 90-95% capacity, saving trades for when injuries really bite. The teams which fail are the ones that trade whenever their team falls to 97% capacity. Sure, that trade will give you an extra 3% capacity. But you'll be operating at 75% capacity by round 18. It's that simple.
And injuries/restings hit hardest in the last couple of rounds. Last season it was Pavlich/Shaw/Didak/Mackie all at once. That's four of my best premiums going down. This happens every year. When a premium goes down and you've already cash cow cycled down to a weakish rookie player as your ressie, that's 50 points per round at least right there.
IF you insist on operating at 100% capacity, you will last twelve rounds and then die. You can test your luck if you want. But let us bookmark this thread so that we can come back in 17 weeks time.