The Bills six-member draft class is all under contract. Top pick Ronald Darby was the last to sign his rookie deal Tuesday at One Bills Drive.

Darby (5-11, 193), Buffalo's second-round pick in the 2015 NFL draft, is a fleet-footed cornerback with solid cover skills, which were on display in the team's rookie minicamp 10 days ago.

"Athletic, fast, that's why we drafted him," said defensive coordinator Dennis Thurman in describing Darby. "Looks like a pretty good man-to-man cover guy from what we saw in the rookie minicamp, but he hasn't gone up against the big time NFL receiver. Usually if you can cover, you can cover. It usually doesn't matter who it is, but he's been pretty impressive so far."

The Florida State product will get his first look at the top end of Buffalo's receiving corps once OTA practices begin next Tuesday.

"I just have fun in practice. I like to practice," Darby said. "I just like to go out there and compete and be prepared for the most part."

Darby is going to fit in nicely with what is widely seen as a deep unit at cornerback with veteran Corey Graham, Stephon Gilmore, Leodis McKelvin and incumbent nickel back Nickell Robey the top four from last season. As Thurman sees it things are wide open right now.

"You look for competition. You want competition," Thurman said. 'We want to put our guys in situations where you see what they have. We have a very talented secondary and at this point you don't want to hand anybody anything. You want them to earn it. They'll be tremendous competition at corner."

And Darby expects to be right in the middle of it.

"I'm going to compete. I've been in a program that has shown that," Darby said. "I believe it was 27-and -one. I'm not used to losing so I get it stuck in me to prepare. I'm going to come prepared, I'm going to come with skills, speed—something that's hard to come across, and just going to try to contribute from day one."