It's not unusual for colleges to have pipelines to certain high schools - usually it's a longtime connection of someone on the staff.
In this case, it may be a player. Harrington, a cornerback from the Class of 2011, has been helping the program on and off the field.
"He is a very talkative and popular kid in the area and at the school and he was a big factor is getting the others there," Rivals.com national recruiting analyst Mike Farrell said. "Once De'Jon Wilson flipped from Kansas to Colorado, he was able to flip Crawley from Tennessee to join him."
Of course, the H.D. Woodson staff helps a bit, too.
Assistant coach and recruiting coordinator Wayne Johnson loves the relationship the school is building with Colorado.
"I know they don't normally recruit this area but they are the best," he said. "I can only say great things about [Buffs defensive coordinator and secondary] coach [Greg] Brown and [defensive ends] coach [Kanavis] McGhee. They have done a marvelous job of recruiting our young men."
Kelly would be the latest get.
Kelly, who has also received an offer from North Carolina, plans to take an unofficial visit to Chapel Hill in early April to watch the Tar Heels practice.
"I have been talking to their coach (North Carolina defensive coordinator Dan Disch) and he wants me to sit in on the meetings before practice," Kelly said. "He had my highlight tape for like a day or two and called me back and he offered right then. That shows he really wants me to be part of their program.
"A lot of schools want to see me in person first before they decide if they are going to offer or not. I am going to work out at H.D. Woodson on May 1 and May 2 and a lot of coaches are going to be there. I should get more offers, a lot more offers, after that."
West Virginia, Virginia, Tennessee, Virginia Tech, NC State, Maryland and Clemson are among the other programs that have shown some form of interest in Kelly.
"I want to get a great education. I want to study Business," he said when asked which factors will weigh heavily in his college decision. "I also want to go to a tradition based program and a program that is family based where they protect each other and look out for each other."
Kelly maintains a 3.0 GPA. He is on pace to be a December graduate from high school.
If Kelly should pick Colorado, he may get a chance to come with an old friend. The school also has offered Kelly's old teammate at Carroll, linebacker Jermaine Carter.
But if you think Colorado is moving away from Woodson, think again.
It already has offered H.D. Woodson cornerback D'Andre Payne, who is expected to be one of the top prospects in the D.C. area from the Class of 2014.