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.