The Kansas City Chiefs are more than a week into training camp and although I haven't seen every rep I can tell you that the biggest development for the Chiefs has been Marcus Peters.
Peters was the Chiefs first round pick in May but the Chiefs are getting their first extended look at him during camp because his college was on the quarters system and prevented him from participating in OTAs outside of the final mandatory minicamp.
One of Peters' strengths was said to be his physicality in press coverage, which you need pads and a full contact practice to truly show off. Once the Chiefs got in pads, Peters showed why he was a first round pick with three interceptions and another one batted down.
Like I said I haven't seen every practice but from what I have seen Peters looks like an NFL cornerback. He has the size. He seems to understand the game as evidenced by his early interceptions. He has good coaches. He will have his rough stretches where a Peyton Manning or an Aaron Rodgers makes him look silly but from what I have seen he has an NFL future.
Of course, this is just one week of one camp. Jon Baldwin was a camp all-pro so I'm hesitant to make any declarations here but I haven't seen anything yet that is drawing any red flags.