Jones impressed with off the charts athleticism at the combine.
Roberts wasn't invited to the combine, so how does his athleticism stack up? From NESN: "He ran a 4.38-second 40-yard dash at his Marshall pro day with a 6.66-second 3-cone drill, 4.06 second short shuttle, 39-inch vertical leap, 11-foot, 1-inch broad jump and 23 reps of 225 pounds on the bench press.
Had Roberts been invited to the combine and put up the same numbers, he would have ranked second among cornerbacks in the 40-yard dash, second in 3-cone, seventh in short shuttle, sixth in vertical leap, second in broad jump and second in bench press."
Read more at:
http://nesn.com/2015/05/patriots-cornerback-roster-reset-darryl-roberts-adds-elite-athleticism/
For comparison, Jones was a tad slower on the three-cone, a bit faster on the short shuttle, five inches higher on the vert leap, and 1'2" longer on the broad jump (and 8" over the previous broad jump record, half of which was held by Jamie Collins).
Looks to me like Roberts is almost as athletic, but not quite. He's also two inches shorter, 5'11" vs. 6'1" for Jones. That's raw talent, real question is what does he do with what he's got? We will see, soon enough.