Absolutely many players do improve. Quite honestly, unless you're improving, then you're regressing. There is no standing still.

But I think there are limits on that improvement. And I think that in general, the amount of 'improvement' you can expect from a given player is pretty marginal - i.e., not really all that earth shattering.

What I mean is this:

I think a player can go from "absolutely unplayable" to "serviceable, maybe even 'league average' type, given the right situation, the right coaching, etc.

And I think some players can start off as "maybe league average type" to "really, really good".

But I do NOT think a player can start out being borderline unplayable, and end up 'really good'. I think that if the makings of a 'really good to great' player are there, it shows pretty much from day one. Probably not in 'consistent results' in year one, but you can clearly, obviously see the signs.

As recent examples, I would look no further than B.J. Raji and Clay Matthews. From year one, to my eyes at least, it was obvious what kind of players they would become. But they looked, to me, pretty outstanding right from day 1.

And I could name TONS of examples of guys who started out 'kind of iffy', but found their footing and eventually blossomed into very solid, some even what you would call 'good' players. I'd put the Rasheed Walkers and Sean Rhyans of the world into that category. Their first years, neither looked like they even needed to be on the field. Now, they're both pretty ok. But neither is so lights out great that GB will have any interest in re-signing them... they're the kind that are just good enough to get seriously overpaid by another team, and the new team will immediately have buyer's remorse as soon as they take the field (as in, we're paying HOW MUCH for this level of play?!?!?!?!).

And I think we all could give PLENTY of examples of guys who started out awful, continued to be awful, and ended up awful and off the team. (J'Mon Moore, Amari Rodgers, etc.)

The ones I really don't get are the ones who have a fairly decent rookie year, but then actually get worse, and end up cut/released/allowed to walk after their rookie contract is up, go somewhere else, and are never heard from again. The two DB's in 2017 (was it?) - Randall and Rollins... heck even Darnell Savage falls into that category for me. What the heck happened there?!?! And really, even the worst OL in Packer history, Royce Newman, falls into that category - his rookie year was by far his best. How TF does that happen?!?!

But can anyone name one player - just one - who started out absolutely terrible... looked like he absolutely didn't belong on the field AT ALL... and suddenly, 15 years go by and we're unveiling his bust in Canton?

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What I'm saying is that for most players (there almost HAVE TO be a few exceptions), they establish their own personal floor and ceiling the first day they step on an NFL field. And there is a pretty limited range between the two. Instances of a guy starting out as an absolute zero, and turning into Jerry Rice, are extremely few and far between. So yes, players do improve. But there's a limit to just how much improvement there can be. For a lot of guys, the manager's saying from Angels in the Outfield fits well: "There's a thing called talent. They don't have it."

I do think that the limitations of the current CBA - practice time limits, and even limits on team-player contact other than when they're 'officially' engaged with the team - are a BIG reason why. They are doing young players a serious disservice, and over time, the overall quality of play in the league is eroding because of it.