You may occasionally suffer an injury to your keeper on the odd game you decided to risk not having a sub keeper. You can play any other player there just like in real life. I usually go for the one with the best handling stat, not formation penalty is applied. oh I have been beaten by teams playing non GK's in goal. T11 does not appear to penalise heavily for out of position players provided they play near their designated spot so a DC is best choice in this case.