One thing that stands out to me about Conner is when he was in Pittsburgh he had the label as being fragile. He seems to have overcome that in Arizona. So if he can do it, we really need to think hard when we label a player as fragile and that it will last forever.
No significant improvement with him with regards to injuries. Missed games every season in Arizona like he did in Pittsburgh, usually good for 3-4 missed games a season. If injuries are why the Steelers wanted to move on I can't say they erred as Najee's been arguably the most durable RB in the league since he came into it but it does not look they used a first round pick to actually get more talented at the position.
Arizona/Gannon loves Conner though. When they signed him a few years ago I never thought he'd see the last year of his contract but he will.