Based on their college film, Sony, easily; he looked like Kamara 2.0.
He's been a totally different player since coming to the NFL, regardless of OL struggles (two separate issues), and in spite of his postseason success last year. Chubb has looked like the better NFL player.
Sony still shows good vision and power at times, but nowhere near the shifty, explosive playmaking ability he showed at UGA; he's much more upright and seems stiff. It's not really debatable that he's been a totally different player at the NFL level when compared to UGA -- just go watch some highlights of Georgia compared to Pats side-by-side and you'll see the difference.
That's not to say he hasn't been productive, he's been a productive contributor, but a totally different style of play.
I really wonder if it's a mental/coaching thing related to ball security, and he's so focused on protecting the ball that he isn't playing loose and aggressively. In the preseason game against Carolina this season he looked like his explosive self at UGA, and I remember posters being blown away and excited by how he looked. But since the start of the regular season that explosiveness hasn't been there.
I don't think it's injuries or a lack of physical ability -- I think it's mental/coaching.
