"I am doing everything. I have been cutting the last couple of days with the guys during the offseason workouts," he said. "I feel like the way I am cutting that I am back to the normal me, man. It feels good to be moving around again. I have been knowing this the whole offseason [that the knee was fine]. Nobody can take nothing away from me except God when my time is up. I am still 30 years old. I still have a lot of special stuff to do."
Charles, 30, was one of the most dynamic playmakers in football before knee injuries slowed him down in recent years. He rushed for 1,000 yards five times and totaled 5,049 yards and 39 touchdowns between the 2012-14 seasons.
He was also a four-time Pro Bowler and two-time first-team All-Pro.
In Denver, Charles' role remains up in the air. If he can remain healthy, he'll give the team at the very least a dynamic third-down back. At best, he could give the Broncos an excellent thunder-and-lightning pair with C.J. Anderson. If he returns to his pre-injury form, the Broncos will have another thrilling weapon to pair with Demaryius Thomas and Emmanuel Sanders.
Charles certainly has something to prove to those who don't believe he can make an impact.
"I like proving people wrong," he told Renck. "It keeps the fire going, it keeps the spark going. I am excited about just getting back to where I was before."
He's also excited to play for the Broncos this upcoming season.
"I have that chip on my shoulder, man. But why am I still playing? It is to get that ring," he said. "I am on a nice team. I really think we can make a run. We have a nice schedule. Our defense is nice. Our offense is going to be nice. We've got the coaches. I know a lot of people are probably not counting us in. But we know behind the scenes. We are definitely counting ourselves in."
The Broncos have the offensive weapons and elite defense to make a deep playoff run, but their quarterback play will likely dictate whether they can return to the postseason. A healthy and effective Charles would go a long way toward that goal as well.