Have you changed orders? ..how you play them as well as opp's orders do seem to affect chance of injury.
Is your pitch fully upgraded? ..it *does* lower the odds.
Are you playing tired players? ..they should be green, 90% or more at match start.
Are your players attribute all weighted to defense or attack? ...they need physical too.

Injuries happen no matter what.. it is part of the game.

Remember it is often cheaper to replace a guy for a token or 5 than spending 15 red packs to fix him, so unless he is a "core" player it is more economical to sell & replace.