I had that same issue when I first joined and in my first league.Special teams were horrendous!!!!! Try going into overrides and substituting guys with SPD,ACC,TCKL,etc. and see if that helps.Of course if there is a lack of talent,not sure what to advise in that regard.And for what it is worth,try not to use all starters either( since the injury rate is higher on Sp Teams),use some of the rookies( to get their skill levels up for later) and some younger Def players. Hope that helps ....