I posted one of the articles that looked at injuries correlated to weight in one of these threads. I think it looked at injuries from 2007 to 2015. I'll see if I can find it, but feel free to look if you're interested. But the conclusion was that injuries were lower across almost all positions on the lower ends of the weight ranges (the exceptions were RB, OL and TE). So, for example, that wasn't saying you would want 150# CB. It was saying that in the normal range for an NFL CB (hypothetically 175-210 or so), there were fewer injuries for the players in the lower range than the higher range. It didn't give a concrete reason, but speculated that lighter players put less stress on on tendons, joints and other soft tissues than heavier players. I also think that play style is a large factor. If you're the guy who is always looking for contact then you will be injured more often than the guy whose body is exposed to less contact.
That was just one article, but I have looked at this issue over the last two decades and literally
every single study or analysis has failed to find more injuries for smaller players. And several have found more injuries among the heavier players. I always find it interesting b/c fans consistently say that bigger players are less likely to get injured and for most positions there is no factual basis for such a belief and considerable evidence against it.
Edit: here is my old post:
NFL football is a violent game, and traumatic injuries are unfortunate but unavoidable. But are bigger players more likely to be hurt than their smaller peers?
www.footballoutsiders.com
This was a study that related weight and injury correlation across different positions.
"For most positions, higher weight is now associated with a higher injury rate. This provides some evidence for our hypothesis that the greater impact forces heavier players experience lead to higher injury rates.
There are two major exceptions to this trend. Heavier running backs exhibit lower injury rates than their lighter counterparts. This may be because of differences in the way heavier running backs are used. Our running back category included both halfbacks and fullbacks, so instead of an effect of weight we may simply be seeing that fullbacks or heavy halfbacks receive fewer carries and thus have fewer chances to get hurt. Supporting this hypothesis of "confounding by role" is a small negative correlation between weight and rush attempts among running backs in 2016 and 2017.
Injury rates also drop among the heaviest tight ends (271 to 290 pounds). Similar to running backs, confounding by role may be an explanation. The heaviest tight ends may be primarily blockers rather than receivers, and blocking is likely a lower-risk activity than running routes and being tackled post-reception.
The heaviest offensive linemen (more than 350 pounds) also exhibit lower injury rates than their lighter counterparts, but confounding by role is less likely to apply here. I do not have an explanation for this decline besides random chance."
They concluded:
"All else equal, if a team has a choice between a 180-pound defensive back and a 210-pounder, they may want to go for the lighter guy."
I thought this was interesting b/c it is the opposite of what I find most fans believe. Most fans seem to assume that all things being equal you should take the heavier guy. Their conclusions mirror what I have seen in every single study on this over the years. I've seen comments posted about it "being fair to be concerned" about Smith's lower weight, but it really isn't to anybody who is basing their opinion on facts.