It's all luck.

Just played my 9th game this season and got my first injury. I play hard tackling and whole pitch pressing, I've got over 600 red packs saved up so that blows the theory of holding them increases risk.
For ever player that gets two or three injuries a day and gets driven crazy, there will be another player who doesn't get these injuries and so doesn't notice it.
Just cry when it happens to you, man up and wait till your luck turns!