I think I must be one of few people on here that doesn't complain about injuries. I really think my plan of adding a lot to my players physical stats is one thing I do differently that contributes to less injuries. (besides fully upgraded pitch) Everyone but my GK has their physical above their main skill set, most of them by at least 5 points. ST's and MC's closer to 10 above. I originally started upping physical when my favorite ST got hurt a couple times in a season and have been doing it since because it works for me, usually I end a season with more red packs than I had at the start. I would say try adding a lot to the physical stats of the guy(s) that get hurt a lot that you don't want to sell.
You can see which players I haven't had as long, their skills aren't as far apart yet.