He ran the 40 at the combine at 4.37 seconds, Deion at 4.22. So he's fast but Greedy didn't look very good in the field drills and showed some issues in his technique. He reportedly lacks instincts and awareness and doesn't play as fast as he runs. He did not do well against either Georgia or Alabama last year but they can make anyone look badly. He also doesn't do well in a zone or off-man coverage, his strength is in man coverage.
He's 6-3, 185 so he is not particularly strong and will really need weight room work. With all that said, he's still a very good player but the whole "avoids contact" would be a concern to me. If he turns out as good as Deion, I will stand corrected but not sure I want the Rams to toss the dice on that.