Just my opinion of course but here's the logic.

If he gets injured early enough, he may come back in time for the playoffs if you need him and then would be injury free.

More likely...he won't get injured for some time and you'll get all or most of his PA's used before he is injured while if you sit him till mid-season and then he gets injured for the rest of the season the first time you use him, you'll get almost no use out of him.

Of note...he will NOT become overused until he is WORN OUT and even at 180% usage he won't have his stats degraded. The game doesn't enforce usage on players with major injuries under the concept that since they are going to get injured it would be a double penalty to limit their usage (I didn't state that well, but suffice it to say you can ignore usage and if he gets "WORN OUT", well you got every last bit of value out of him.